Glass

Detail of a medieval window at Troyes Cathedral, France (14th century)
GLASS
ABUILDINGMATERIAL
MITALI VAVRE MCO001
SAMRUDDHI GIRI
MCO009
PRANAY TODE
MCO013

Glass is an amorphous non crystalline, hard, brittle, insoluble, transparent or translucent super cooled liquid of
infinite viscosity, having no definite melting point obtained by fusing a mixture of a number of metallic silicates
or borates of Sodium, Potassium, Calcium, and Lead.
• It has widespread practical, technological, and decorative usage in, for example, window panes, tableware,
and optoelectronics.
• It is a vitreous material such as flint and obsidian do occur in nature but glass is made artificially by rapid
cooling of a molten mixture of silicate minerals such as Quartz, sand and crushed flint.
• It possess no definite formula or crystalline structure.
• “An inorganic product of fusion which has cooled to a rigid condition without crystallizing”
• It does not have a specific melting point.
• It Softens over a temperature range.
INTRODUCTION

GENERAL PROPERTIES OF GLASS
Glass is:
• Amorphous
• Brittle
• Transparent / Translucent
• Good electrical insulator
• Unaffected by air, water, acid or chemical reagents except
Hydrogen Fluoride
• No definite crystal structure means glass has high Compressive strength
• Can absorb, transmit and reflect light
RAW MATERIALS USED IN MANUFACTURING GLASS
• Sodium as Na2Co3 (used in soft glass).
• Potassium as K2Co3 (used in Hard Glass).
• Calcium as lime stone, chalk and lime.
• Lead as litharge, red lead (flint glass).
• Silica arc quartz, white sand and ignited flint.
• Zinc is zinc oxide (Heat and shock proof glass).
• Borates are borax, Boric acid (Heat and shock proof glass).
• Cullets or pieces of broken glass to increase fusibility.
SiO2
72%
Na2O
13%
CaO
12%
Al2O3
2%
Minors
1%
TYPICAL GLASS COMPOSITION
SiO2 Na2O CaO Al2O3 Minors

MANUFACTURING STEPS
1. Melting
2. Forming and Shaping
3. Annealing
4. Finishing
Cullet - recycled broken or waste glass used in glass-making.
Anneal - heat (metal or glass) and allow it to cool slowly, in order to remove internal stresses and toughen it.

MELTING PROCESS
Raw materials in proper proportions are mixed with
cullets. It is finely powdered and intimate mixture called
batch is fused in furnace at high temperature of 1800°C
this charge melts and fuses into a viscous fluid.
CaCO3 + SiO2  CaSiO3 + CO2 
Na2CO3 + SiO2  Na2SiO3 + CO2
After removal of CO2 decolorizes like MnO2 are added
to remove traces of ferrous compounds and Carbon.
Heating is continued till clear molten mass is free from
bubbles is obtained and it is then cooled to about
800°C.
Cullet is recycled broken or waste glass used in glass-making.
The viscous mass obtained from melting is poured
into moulds to get different types of articles of
desired shape by either blowing or pressing between
the rollers.
FORMING AND SHAPING

Glass articles are then allowed to cool gradually at
room temperature by passing through different
chambers with descending temperatures. This reduces
the internal Strain in the glass.
Finishing is the last step in glass manufacturing.
It involves following steps.
• Cleaning
• Grinding
• Polishing
• Cutting
• Sand Blasting
ANNEALING FINISHING

VARIETIES OF GLASS
NAME CONTENTS PROPERTIES PHOTO USES
1. SODA LIME OR
SOFT GLASS
Na2CO3.CaO.6SiO2.
silica (sand), Calcium
carbonate and soda ash.
low cost, resistant to
water but not to acids.
They can melt easily and
hence can be hot
worked.
Window glass, Electric
bulbs, Plate glass,
Bottles, Jars, cheaper
table wares, test tubes,
reagent bottles etc
2. POTASH LIME OR
HARD GLASS
K2CO3.CaO.6SiO2.
silica (sand), Calcium
carbonate and
potassium carbonate.
high melting point, fuse
with difficulty and are
less acted upon by
acids, alkaline and other
solvents than ordinary
glass.
chemical apparatus,
combustion tubes and
glassware which are
used for heating
operations.
3. LEAD GLASS OR
FLINT GLASS
K2Co3.PbO.SiO2
lead oxide fluxed with
silica and K2CO3
lower softening
temperature and higher
refractive index and
good electrical
properties. It is bright
lustrous and possess
high specific gravity.
Windows and Shields
for protection against X-
rays and Gamma rays in
medical and atomic
energy fields etc.

NAME CONTENTS PROPERTIES PHOTO USES
4. BOROSILICATE OR
PYREX GLASS
SiO2(80.5%), B2O3(13%),
Al2O3(03%), K2O(3%)
and Na2O(0.5%).
low thermal coefficient of
expansion, and high chemical
resistance i.e.. shock proof.
Industrially used for pipeline of
corrosive liquids, gauge glasses,
superior laboratory apparatus,
kitchen wares, chemical plants,
television tubes, electrical
insulators etc.
5. ALUMINO- SILICATE
GLASS
SiO2(55%), Al2O3(23%),
MgO(09%), B2O3(07%),
CaO(05%) and Na2O,
K2O(01%).
exceptionally high softening
temperature.
It is used for high pressure
mercury discharge tubes,
chemical combustion tubes and
certain domestic equipments.
6. 96% SILICA GLASS 96% Silica, 03% B2O3
and traces of other
materials.
translucent, the coefficient of
thermal expansion is very low
hence it has high resistance to
thermal shock, have high
chemical resistance to corrosive
agents and are corroded only by
Hydrofluoric acid, hot
phosphoric acids and
concentrated alkaline solutions.
Used only where high
temperature resistance is
required (800°C). They are used
in construction of chemical
plants, laboratory crucibles,
induction furnace lining and
electrical insulators.

NAME CONTENTS PROPERTIES PHOTOS USES
7. 99.5% SILICA
GLASS(VITREOSIL)
pure silica translucent, the coefficient
of thermal expansion is
very low hence it has high
resistance to thermal shock,
have high chemical
resistance to corrosive
agents.
They are used in
construction of chemical
plants, laboratory crucibles,
induction furnace lining,
electrical insulators and
heaters and have high light
transmission properties.
8. OPTICAL OR
CROOK’S GLASS
Phosphorus, PbCO3,
silicates and Cerium oxide
low melting point and are
relatively soft.
They are used for making
optical lenses.
9. POLY-CRYSTALLINE
GLASS
adding nucleating agents to
a conventional glass batch
and then shaped into
desired form.
high strength and
considerable hardness.
For making specialized
articles.

10. TOUGHENED GLASS dipping articles still hot
in an oil bath, so that
chilling takes place
more elastic to
mechanical and thermal
shock. It breaks into a
fine powder.
For making window
shields of fast moving
vehicles, windows of
furnace and automatic
opening doors.
11. INSULATING GLASS Two or more plates of
glass are filled with
dehydrated air and the
edges are
Good insulators of heat
and light.
Provides thermal
insulating and so houses
remain cool in summer
and warm in winter.
12. WIRED GLASS fusing wire in between
the two glass layers
does not fall apart into
splinters when it breaks
and is fire resistant.
fire resistant doors,
roofs, skylights and
windows

13. GLASS WOOL tiny fibers formed by action
of steam jets on dripping
molten glass down from
very fine hole.
Sound and Heat Insulation Heat Insulation, for
filtration of Corrosive
chemicals, sound insulation
etc
14. LAMINATED GLASS The sheets of glass fiber or
glass wool are soaked in a
solution of thermosetting
plastic like phenol
formaldehyde resin and
placed one above the other
and then cured under heat
or pressure.
It is strong as steel. Non
flammable and insulating.
In bullet resistant glass vinyl
resins are added in
alternate layers.
Shatter, shock and Bullet
proof Glass
15. FIBER GLASS high tensile strength. Found extensive use for the
manufacture of fabric,
reinforcing plastics and
production of thermal
insulation materials etc

16. PHOTOSENSITIVE
GLASS
potash-alumina glass,
mixed with LiSO3,
cerium and Silver salts
glasses by which a
colored picture may be
developed by exposing
the glass to black and
white negative in ultra
violet light.
Photographic
development
17. PHOTO-CHROMIC
GLASS
SILICA The three dimensional
silicate network contains
large no. of microscopic
particles of silver halide
which on exposure to
light produce color
In making tinted car
glasses and goggles.
18. NEUTRAL GLASS alumina, boron oxide
and zinc oxide.
These glasses are highly
resistant to chemical
attacks
Making Syringes,
Injection Ampoules and
vials etc.

19. COLORED GLASS coloring pigments
added to glass to give
desired color to desired
properties
DIFFERENT Decoration purposes.

VARIABLE PROPERTIES OF GLASSES
As the sizes of glass sheets used in buildings increase, the need to understand the physical characteristics of selected glasses also increases.
Density and stresses.
• The density of normal window glass is about 2.5 (i.e. equivalent to aluminum) but lead crystal approximates 3.1 and some optical glasses equal 7.2.
• In structural properties. sheet glass is very strong in compression. When it breaks it does so in tension. Toughened glass will withstand impact loads greatly in excess
of sheet glass capability.
• Laminated glasses can prevent dangerous shattering in accidents.
Thermal Properties
• Thermal expansion is important as a factor in the resistance of glass to heat shock, and in determining the stresses set up in windows under alternating heating and
cooling. In glass-to-metal seals, the expansions of glass and metal must match closely over the range of temperatures in which glass cannot yield to stress.
• Thermal endurance or the ability to resist temperature contrasts is important in such items as cooking utensils and some industrial building situations.
• Special glasses such as Pyrex have been developed that can resist shock of 300 deg C. Normal window glasses can tolerate approximately 130 deg C, which generally
is adequate.
• The thermal conductivity of glass varies considerably according to its constituents, some glasses being three times more conductive than others.
• The range of values is from 0.0028 to 0.0078 calories per centimeter per degree centigrade per second. For most building purposes, manufacturers can provide more
meaningful values for each type marketed.
Light absorption and transmission
• Of the white light falling on glass at right angles to the surface. some is reflected, some absorbed, and some emerges at the other surface.
• The degree of absorption varies with different wavelengths, so the emergent light is different from the incident light.
• The extent of the absorptions depend on glass composition and thickness for building situations. Glasses very low in iron content transmit ultraviolet light: a high
ferrous iron content cuts off both ultra-violet and heat radiation: nickel oxide content obstructs visible light but transmits ultraviolet.
• Glass manufacturers should be consulted where large quantities or sizes of glass arc contemplated, as their recommendations and advice can affect greatly the whole
specification and detailing of glazed openings. Obviously. consultation during the early stages of building documentation is most desirable.

HISTORY OF GLASS
Glass fulfils such an important role in architecture that it is difficult to find
buildings which do not rely at least to some extent on its combination of
transparency and weatherproofing. Solid-walled buildings use glass windows
to let in light and air whilst keeping out rain and wind, and much modern
architecture relies on walls and even roofs of glass.
Glass making seem to have been
invented in north-western Iran
around 2200 BCE and by the time
Egyptian New Kingdom(1600 BE)
colored glass was being used for
furniture and for architectural
inlays.
By the beginning of Industrial revolution new industrialized processes the
made manufacturing of the glass easier. Prices dropped and by the end of
20th century it became the primary building material.

MAKING
Broad-sheet glass and early cylinder glass
1765, shows the various steps in the process:
forming the cylinder, cutting of the ends, slicing
down the middle, and finally flattening it on a
special table.
Crown glass
1772, open bubble being heated and
spun on the furnace, and then spun over
a depression in the ground. To allow the
largest possible sheet to be made. Size of
the sheet will be limited to the size of the
opening.

Windows in the workshop needed to let
the light in and keep the weather out, but
it was not necessary for either workers or
passers-by to see through them. So bull’s
eye were commonly used.
Handmade plate glass
1765, shows the plate being cast on a
metal table, which could be heated from
beneath to anneal the glass.
The plate would be then transferred to
another table for polishing.
The crystal palace, London, being
dismantled around 1859.

DETERIORATION AND DAMAGE
Glass is one of the most stable building material: it sis essentially
impermeable, and unless it is poorly made, it does not easily
corrode. Its main weakness is that it is extremely brittle, so that it
fractures catastrophically under the load rather than deforming.
FRACTURE-
The resistance of a particular piece of glass to stress will depend
on many things –
•chemistry and microstructure
•Size and thickness
•Whether or not, it has been annealed or tempered
•Nature of the load.
Annealed glass can withstand surprisingly high bending
stresses, but internal flaws and inclusion, and surface scratches
and corrosion, will all form places for cracking.
Sudden loads are therefore likely to cause shattering.

CORROSION-
•Most corrosion of architectural glass is associated with
moisture, often because of condensation or rain. Pure water
is acidic and its pH value will be often be further reduced by
pollutants, and by other soluble contaminants(such as salts)
taken up from the surface deposits on the glass and
surrounding material.
•The acidic water leaches out the alkalis in the surface of
the glass by a process of ion exchange –
The hydrogen ions in the water replace the sodium and
potassium ions in the glass matrix. Since the hydrogen ions
are much smaller, this makes the surface more porous,
which increases the area of contact with the corrosive
solution. Eventually the surface becomes a silica-rich gel,
this is known as crizzling.
The progress of this type of corrosion is hard to predict, and
will vary with the exact conditions.

ABRASION-
Glass surfaces can be damaged by chemical or
physical abrasion, producing fine scratches the reduce
the transparency by refracting the light. The
roughened surface will also trap dirt and other
contaminants.
DISCOLORATION-
•Under high magnification, it can be seen that the surface of
new glass is not perfectly smooth, but has pits that can
easily be filled by contaminants. If these are able to
chemically bond with the glass, it will be discolored.
•Over time, cleaning may abrade the surface, and the sow
process of glass corrosion may make the surface rougher
as well. Thus glass becomes more likely to discolor.

CAUSES OF DETERIORATION
1. Original materials and design
• Glazing will deteriorate is its design, material or construction are unsuitable
to cope with day-to-day use, or with the Conditions in and around the
building.
• The adequacy of any Building features needed to protect the glazing will
also have an impact. Another common fault is due to poor design, poor
manufacture , or poor installation.
2. Structural movement
• Changes to the way loads transfer through the building structure will often
most visibly affect the glazing. Frames may be distorted and panes may well
crack, especially in fixed glazing where the glass has too little allowance for
movement.
3. Environmental conditions
• Deterioration can be caused due to the location and its surroundings, the
local climate, the condition inside and also the usage of a room. It also
depends on the design , particularly the way it handles structural stresses,
rainwater and groundwater, and on the construction materials.
• Its is susceptible to breakage , which can arise from problems as diverse as
structural movement or vandalism.
• Very low thermal inertia means it will respond quickly to temperature
changes, reacting to fluctuation air temperature, the wind and the sunlight.
Some 19 the century glass windows with
inadequate structural support tend to sag

Moisture
• If glass is exposed to standing water for a long periods
(whether the source is precipitation or condensation), it may
corrode.
• Problems may well be exacerbated if there are any salts or
other pollutants present as well, since these may be activated
by moisture.
• Exterior glazing is often exposed to rainwater, but since
window, roofs and curtain walls are designed to be washed by
rain, this is rarely a problem unless the glazing is poorly
designed.
Temperature
• Glass is a poor thermal conductor, so heating one area of the
surface can cause differential movement within the material,
and this can easily lead to fracture.
• Possible sources of localized heat include air temperature,
sunlight and artificial heating.
• Heat can be particularly problematic for decorated glass.
Differential expansion and contraction can cause applied
decoration to flake away from glass, and even small
increases in temperature can damage the binding materials
used in painting and gilding. Decorative or protective films
applied to modern glass are equally susceptible to
deterioration from this cause.
• Metal frameworks will shrink or expand in response to
temperature change, sometimes results in shattering of glass.

Solar radiation
• Glass coatings and decoration can be damaged by
sunlight, not only because of local temperature increases,
but also due to UV rays attack the binders. This may also
lead to discoloration of the glass.
• Exposure to sunlight therefore limits the lifespan of many
critical glazing components.
Wind
• Glass subjected to wind load on both sides of the
building windward and lee side get affected due to
push and pull forces respectively.
• The wind patterns are complex and variable: they will
depend on the shape and size of the building and its
surroundings.
Pollution
• Glass up to 5kms or more inland may receive deposits of
wind blown chlorides.
• In industrial areas the levels of sulphur-dioxide and
hydrogen chloride are high.
• Although sulphuric-dioxide do not attack glass directly , it
can perpetuate glass corrosion by forming hygroscopic
crusts on corroding surfaces.
• It may not always be the deterioration of the glass but also
the support system which may in return affect the glass.

Biodeterioration
• If the glass is rough because it is painted or scratched or
corroded, bacteria, lichens, algae and fungi may begin to
grow.
• The acidic secretion can exacerbate corrosion by releasing
mineral components from the glass and also feed on the
binder materials.
Interior environment
•Below due point the surface of glass will form a film of water
which is not noticeable, which lead to moisture related problems
such as glass corrosion and deposition of dust.
•Moisture formed due to the process of condensation caused
because of temperature changes in and out side the room.
•Ventilation is often used to try prevent condensation, but if not
handled carefully the result can be counter- productive.
•Pollutants created due coal fire heating systems and in kitchens .
These emit sulphates and other pollutants. Further is combined
with moisture might lead to accommodation of dust and dirt and
provide an ideal habitat for micro-organism.

4. OTHET PROBLEMS
-PREVIOUS TREATMENTS AND REPAIRS
•Cleaning
For the glass to function as it intended to the architectural
glass must be cleaned regularly and with appropriate
techniques. Usage of metal tools, wire wool, alkaline and
acidic solutions results in discoloration and corrosion
•Surface coatings
Plastic films adhered to glass to cut down the transmission
of the UV rays will degrade over the time, bubbling and lifting
from the surface. This is unlikely to cause damage to the
glass surface unless it is fragile, but damage may have been
caused by attempts to remove a deteriorating film.
•Poor repairs
Glass in mostly historic buildings are been replaced . It can
dramatically alter the appearance of the building and not all
the resulting changes to the interior conditions will have
proved beneficial for the occupants or the building fabric.
-DAMAGE FROM FORSEEN EVENTS

ASSESMENT
ASSESSMENT OF GLASS
No matter how good any treatment or repair might be, It will not be enough to preserve the glazing if the underlying
problems are not dealt with first, so before any work are planned, commissioned or undertaken, it is important to allow
sufficient time for investigation and assessment.
Information
Background
research
Condition
surveying
Special
Investigations

ASSESMENT
Effective assessment depends on following
criterion and gathering information about:
• The history of glazing (including the original
materials and design, and the materials and
methods used in past treatments and
repairs).
• The problems and failures that have affected
it, past and present.
• Its current condition.

1. Good assessment
• Background Research:
• Methodology:
• Condition Survey:
• Recording a Condition
Survey
• Selecting a Recording
Technique
• Recording Techniques:
• Drawings
• Photography
• Laser Scanning
• Mapping Condition
2. Environmental Assessment
3. Material Assessment
4. Functionality Assessment
5. Reporting
Specialist Investigation:
Identifying materials
Glass:
Identifying glass is essential for understanding nor only the history of the
glazing but also the damage and deterioration.
Chemical analysis can provide some information about the date of
manufacture, and may also help explain why the glass has deteriorated.
Deposits on the Glass:
Deposition of algae and moulds is a serious issue, to determine effective
control it may be necessary to identify then exactly.
Materials of the Frames and Supports:
The assessment of materials such as metal, Stone, Timber and Mortar, and
the coating that are used to protect them- including the best methods of
sampling and analysis must be identified thoroughly.
Coatings:
Most frames will have been protected with paints and special coatings, or
with finishes such as galvanising and anodising, which will have painted over.
If the survey has suggested that some remains of historic decorative or
protective coating might survive, the more detailed research may be
necessary to identify and date these, and assess their importance.

Planning Treatment and Repair
Glass needs regular cleaning, frames will need to be protected from water
damage by repainting and renewing seals, and opening windows will need
lubrication and occasional repair to keep them in functional condition.
Some critical materials including coatings and putties and sealants, have
limited lifespans, and will need to be regularly repaired or renewed.
Approaches to Interventions:
The fundamental consideration when planning interventions is the value, or
‘significance’, of the building and its glazing. Historically significant building
and glazing may well be protected by law, but significance has a wider
meaning as well.
The definition of an acceptable level of intervention has changed over time.
For much of 20th century damaged or missing glass was automatically
replaced, but this would now be considered poor practice.
Current conservation policies are based on minimal interventions principally
directed at preventing further deterioration.
Whatever the prevailing wisdom, each generation has a duty of care to
preserve the built heritage for the benefit of its successor, and the ways we
approach intervention must reflect this.

GUIDELINES FOR INTERVENTIONS:
1. Stabilise in preference to restoring.
2. Intervene as little as possible (minimal
intervention).
3. Retain as much of the original fabric as
possible, and try to use similar materials
should replacement be necessary.
4. The introduction of new materials
should not adversely affect the
continued performance of the original
materials.
5. Treatments and repairs should be
reversible if possible, or at the very least
should not compromise subsequent
interventions.
6. Monitoring interventions

TREATMENT TRIALS
Although some building materials function
well with little or no intervention, this is not true of
glazing.
ON-GOING CARE AND MAINTENANCE
Since every interventions involves a certain amount
of risks and a certain degree of loss of original
material, ensuring that building conservation is
built around care and maintenance, rather than
treatment and repair, is good practice. By finding
and dealing with problems before they are able to
develop to point where major interventions are
required, the period between major works can be
greatly extended. Care and maintenance is
therefore more than likely to be cost effective,
however difficult it may be to actually quantify the
financial benefits.

Maintenance
The various actions needed to keep glazing in acceptable condition and has several purposes.
• To ensure that the glazing, and indeed the building as a whole, continues to function as well as possible
• To slow down the rate of deterioration
• To limit treatment and repair to small and timely interventions, thus limiting the need for major works.
Regular Maintenance
• Planned inspection at regular intervals
• Implementation of planned works, such as renewing sealants and protective coating and lubricating fittings.
Reactive Maintenance
• Inspection following unforeseen events such as storms or floods, or vandalism
• Implementation of works arising from defects noted during regular inspections and inspections following
unexpected.
Scheduling Maintenance
• Accessibility
• Regular inspections and actions
• Reactive inspections and actions
• Recording inspections and actions
• logbooks
MAINTENANCE
The various actions needed to keep glazing in acceptable
condition and has several purposes.
• To ensure that the glazing, and indeed the building as a
whole, continues to function as well as possible
• To slow down the rate of deterioration
• To limit treatment and repair to small and timely
interventions, thus limiting the need for major works.
REGULAR MAINTENANCE
• Planned inspection at regular intervals
• Implementation of planned works, such as renewing
sealants and protective coating and lubricating fittings.
REACTIVE MAINTENANCE
• Inspection following unforeseen events such as storms or
floods, or vandalism
• Implementation of works arising from defects noted
during regular inspections and inspections following
unexpected.
SCHEDULING MAINTENANCE
• Accessibility
• Regular inspections and actions
• Reactive inspections and actions
• Recording inspections and actions
• logbooks

HISTORY OF GLASS
Naturally occurring glass, especially the volcanic glass obsidian, has been used by
many Stone Age societies across the globe for the production of sharp cutting tools
and, due to its limited source areas, was extensively traded. But in general,
archaeological evidence suggests that the first true glass was made in coastal north
Syria, Mesopotamia or ancient Egypt. The earliest known glass objects, were beads,
perhaps initially created as accidental by-products of metal-working (slags) or during
the production of faience, a pre-glass vitreous material made by a process similar to
glazing.
During the Late Bronze Age in Egypt, there was a rapid growth in glass-making
technology. Archaeological finds from this period include colored glass ingots, vessels
(often colored and shaped in imitation of highly prized hard stone carvings in semi-
precious stones) and the ubiquitous beads. The alkali of Syrian and Egyptian glass
was soda ash, sodium carbonate, which can be extracted from the ashes of many
plants, notably halophile seashore plants: (see saltwort). The earliest vessels were 'core-
formed', produced by winding a ductile rope of glass round a shaped core of sand and
clay over a metal rod, then fusing it with repeated reheating.
FAIENCE
GLASS INGOT

HISTORY OF GLASS
Glass remained a luxury material, and the disasters that overtook Late Bronze Age
civilizations seem to have brought glass-making to a halt. It picked up again in its
former sites, in Syria and Cyprus, in the 9th century BC, when the techniques for
making colorless glass were discovered.
This account is more a reflection of Roman experience of glass production, however, as
white silica sand from this area was used in the production of glass within the Roman
Empire due to its high purity levels. During the 1st century BC glass blowing was
discovered on the Syro-Judean coast, revolutionizing the industry. Glass vessels were
now inexpensive compared to pottery vessels. A growth of the use of glass products
occurred throughout the Roman world. Glass became the Roman plastic, and glass
containers produced in Alexandria spread throughout the Roman Empire. With the
discovery of clear glass (through the introduction of manganese dioxide), by glass
blowers in Alexandria circa 100 AD, the Romans began to use glass for architectural
purposes. Cast glass windows, albeit with poor optical qualities, began to appear in the
most important buildings in Rome and the most luxurious villas
of Herculaneum and Pompeii. Over the next 1,000 years glass making and working
continued and spread through southern Europe and beyond.
HELLENISTIC GLASAMPHORA FROM OLBIA
Ancient Greek glass amphora from the Hellenistic period.

The Industrial Revolution was the transition to new manufacturing processes in the period from about 1760 to sometime between 1820 and 1840. This transition included going from hand production methods to machines, new chemical manufacturing and iron production
processes
HISTORY OF GLASS
THE CRYSTAL PALACE HELD THE GREAT EXHIBITION OF 1851
INDUSTRIAL REVOLUTION
The Industrial Revolution was the transition to
new manufacturing processes in the period
from about 1760 to sometime between 1820
and 1840. This transition included going from
hand production methods to machines, new
chemical manufacturing and iron production
processes.
A new method of producing glass, known as
the cylinder process , was developed in Europe
during the early 19th century. In 1832 this
process was used by the Chance Brothers to
create sheet glass. They became the leading
producers of window and plate glass. This
advancement allowed for larger panes of glass
to be created without interruption, thus freeing
up the space planning in interiors as well as the
fenestration of buildings. The Crystal Palace is
the supreme example of the use of sheet glass
in a new and innovative structure.

HISTORIC GLASS
1. SASANIAN GLASS ( PERSIAN GLASS )
Sasanian Glass(pre Islamic )is the glassware produced between the 3rd and the 7th centuries AD within the limits of
the Sasanian Empire, namely Northern Iraq, Iran and Central Asia. This is a silica-soda-lime glass production characterized
by thick glass-blown vessels relatively sober in decoration, avoiding plain colors in favor of transparency and with vessels
worked in one piece without over- elaborate amendments. Thus the decoration usually consists of solid and visual motifs
from the mold (reliefs), with ribbed and deeply cut facets, although other techniques like trailing and applied motifs were
practiced.
The Arab poet al-
Buhturi (820–
897) described
the clarity of such
glass, "Its color
hides the glass as
if it is standing in
it without a
container."

2. FOREST GLASS
Forest glass (Waldglas in German) is late Medieval glass produced in
North-Western and Central Europe from about 1000-1700 AD using
wood ash and sand as the main raw materials and made in factories
known as glass-houses in forest areas. It is characterized by a variety of
greenish-yellow colors, the earlier products being often of crude design
and poor quality, and was used mainly for everyday vessels and
increasingly for ecclesiastical stained glass windows. Its composition
and manufacture contrast sharply with Roman and pre-Roman glass
making centered on the Mediterranean and contemporaneous Islamic
glass making to the east.
GERMAN DRINKING GLASS OF THE 17TH CENTURY
BEEHIVE DESIGN FURNACE
CATHEDRAL OF ST. DENIS, PARISFOREST GLASSHOUSE OF 18TH CENTURY

3. STAINED GLASS
The term stained glass can refer to colored glass as a material or to works created from it. Throughout its thousand-year history, the term has
been applied almost exclusively to the windows of churches, mosques and other significant buildings. In Europe, the art of stained glass reached
its height between 1150 and 1500, when magnificent windows were created for great cathedrals. Most of what is known about medieval stained-
glass making comes from a twelfth-century German monk who called himself Theophilus.
As a material stained glass is a glass that has been colored by adding metallic salts during its manufacture. The colored glass is crafted
into stained glass windows in which small pieces of glass are arranged to form patterns or pictures, held together (traditionally) by strips of lead
and supported by a rigid frame. Painted details and yellow stain are often used to enhance the design. The term stained glass is also applied to
windows in which the colors have been painted onto the glass and then fused to the glass in a kiln.
STAINED GLASS WINDOW
AT SÜLEYMANIYE MOSQUE
SUNLIGHT SHINING THROUGH STAINED GLASS ONTO COLOURED CARPET
OF NASIR-OL-MOLK MOSQUE
THE NORTH TRANSEPT ROSE
OF CHARTRES CATHEDRAL

3. STAINED GLASS
Stained glass, as an art and a craft, requires the artistic skill to conceive an
appropriate and workable design, and the engineering skills to assemble the piece.
A window must fit snugly into the space for which it is made, must resist wind and
rain, and also, especially in the larger windows, must support its own weight.
In Western Europe, they constitute the major form of pictorial art to have survived. In
this context, the purpose of a stained glass window is not to allow those within a
building to see the world outside or even primarily to admit light but rather to
control it. For this reason stained glass windows have been described as 'illuminated
wall decorations'.
The design of a window may be abstract or figurative; may incorporate narratives
drawn from the Bible, history, or literature; may represent saints or patrons, or use
symbolic motifs, in particular armorial.
Colors:
1. Transparent Glass: Ordinary soda-lime glass
2. Green glass bluish-green: Iron(II) oxide
Rich Green(Wine bottles): addition of chromium
Emerald green: addition of tin oxide
3. Blue glassadding cobalt, which at a concentration of 0.025 to 0.1% in soda-lime
glass achieves the brilliant blue characteristic of Chartres Cathedral.
Borosilicate glasses: sulphur
Turquoise: The addition of copper oxide at 2-3%
Blue, violet, or black glass: addition of nickel, at different
concentrations, produces.
13TH-CENTURY WINDOW FROM CHARTRES SHOWING EXTENSIVE USE OF
THE UBIQUITOUS COBALT BLUE WITH GREEN AND PURPLE-BROWN
GLASS, DETAILS OF AMBER AND BORDERS OF FLASHED RED GLASS.
A 19TH-CENTURY WINDOW ILLUSTRATES THE RANGE OF
COLORS COMMON IN BOTH MEDIEVAL AND GOTHIC
REVIVAL GLASS, LUCIEN BEGULE, LYON (1896

3. STAINED GLASS
4. Red glass
Metallic gold, in very small concentrations (around 0.001%),
produces a rich ruby-coloured glass ("ruby gold"); in lower
concentrations it produces a less intense red, often marketed as
"cranberry glass". Selenium is an important agent to make pink
and red glass. When used together with cadmium sulphide, it
yields a brilliant red colour known as "Selenium Ruby.
5. Yellow glass
Silver compounds (notably silver nitrate) are used as stain applied
to the surface of glass and fired on. They can produce a range of
colours from orange-red to yellow. With calcium it yields a deep
yellow colour.
Adding titanium produces yellowish-brown glass. Titanium is
rarely used on its own and is more often employed to intensify
and brighten other additives.
6. Purple glass
The addition of Manganese gives an amethyst color. Nickel,
depending on the concentration, produces blue, or violet, or
even black glass. Lead crystal with added nickel acquires a
purplish color.
7. White glass
Tin oxide with antimony and arsenic oxides produce an
opaque white glass, first used in Venice to produce an
imitation porcelain.
A WINDOW BY TIFFANY ILLUSTRATING
THE DEVELOPMENT AND USE OF MULTI-
COLORED FLASHED, OPALISED AND
STREAKY GLASSES AT THE END OF THE
19TH CENTURY
A LATE 20TH-CENTURY WINDOW
SHOWING A GRADED RANGE OF
COLORS. RONALD WHITING,
CHAPEL STUDIOS. TATTERSHALL
CASTLE, UK
A 16TH-CENTURY WINDOW BY ARNOLD OF NIJMEGEN SHOWING THE
COMBINATION OF PAINTED GLASS AND INTENSE COLOR COMMON IN
RENAISSANCE WINDOWS

A collection of Anglo-Saxon beads from a cemetery at Sarr
4. ANGLO-SAXON GLASS
Anglo-Saxon glass has been found across England during archaeological excavations of both settlement and cemetery sites. Glass in the Anglo-
Saxon period was used in the manufacture of a range of objects including vessels, beads, windows and was even used in jewelry.
The main type of glass found in the Anglo-Saxon period is a soda-lime-silica glass, continuing the Roman tradition of producing glass.
In the 5th century AD with the Roman departure from Britain, there were also considerable changes in the usage of glass.
CLAW BEAKER FROM AN ANGLO-SAXON
SITE
A COLLECTION OF ANGLO-SAXON BEADS FROM A CEMETERY AT SARR

In the 18th century Murano glassmakers started to introduce new products such as glass mirrors and chandeliers to their production. In history these glass chandeliers became popular after the iron, wood and brass era of chandeliers, and they were such a success that
instantly brought chandeliers to a new dimension.
4. VENETIAN GLASS
Venetian glass is a type of glass object made in Venice, Italy, primarily on the island of Murano. It is world-renowned for being colourful,
elaborate, and skillfully made. Many of the important characteristics of these objects had been developed by the thirteenth century. Toward the
end of that century, the centre of the Venetian glass industry moved to Murano. Despite efforts to keep Venetian glassmaking techniques within
Venice, they became known elsewhere, and Venetian-style glassware was produced in other Italian cities and other countries of Europe. The
process of making Murano glass is rather complex. The glass is made from silica, which becomes liquid at high temperatures. As the glass passes
from a liquid to a solid state, there is an interval when the glass is soft before it hardens completely. This is when the glass-master can shape the
material.
ALDREVANDINI BEAKER, A VENETIAN
GLASS WITH ENAMEL
DECORATION DERIVED FROM ISLAMIC
TECHNIQUE AND STYLE. CIRCA 1330
GOBLET, 1675-1725, VENICE V&A
MUSEUM NO. 108-1853
VENETIAN ARTISANS USE SPECIAL TOOLS INCLUDING: BORSELLE
(TONGS TO HAND-FORM THE RED-HOT GLASS)
ORANGE MURANO BEADS

5. MURANO GLASS
Murano glass is glass made on the Venetian island of Murano, which has specialized in fancy glasswares for centuries. Murano’s glassmakers led
Europe for centuries, developing or refining many technologies including crystalline glass, enamelled glass (smalto), glass with threads of gold
(aventurine), multicolored glass (millefiori), milk glass (lattimo), and imitation gemstones made of glass.
Located 1.5 km (0.93 mi) from the main city Venice, Italy, Murano has been a commercial port since as far back as the 7th century. It is believed
that glassmaking in Murano originated in 8th-century Rome, with significant Asian and Muslim influences, as Venice was a major trading port.
Murano glass is the largest proportion of Venetian glass. In the 18th century Murano glassmakers started to introduce new products such as glass
mirrors and chandeliers to their production. In history these glass chandeliers became popular after the iron, wood and brass era of chandeliers,
and they were such a success that instantly brought chandeliers to a new dimension.
MURANO GLASS FOUNTAIN
WITH FOUR SEASONS. CIRCA
1940
MURANO GLASS PAPER WEIGHTS VENETIAN MURANO GLASS
CHANDELIER. CIRCA 1880
MURANO
MILLEFIORI PENDANT

6. MACKINTOSH GLASS
Charles Rennie Mackintosh (7 June 1868 – 10 December 1928
•City of Glasgow. Located on the banks of the River Clyde,
•During the Industrial Revolution, the city had one of the greatest production
in the world. The demand for consumer goods and arts went high and gained
popularity
•Along with it, Asian style and emerging modernist ideas also influenced
Mackintosh's designs. Japanese design became more accessible and gained great
popularity.
•This style was admired by Mackintosh because it was simple forms and natural
materials rather than elaboration and artifice; the use of texture and light and
shadow rather than pattern and ornament.
•At the same time a new philosophy concerned with creating functional and
design was emerging throughout Europe: the so-called "modernist ideas". The main
concept of the Modernist movement was to develop innovative ideas and new
technology.
•Heavy ornamentation and inherited styles were discarded. Mackintosh took his
inspiration from his Scottish upbringing and blended them with the flourish of Art
Nouveau and the simplicity of Japanese forms.
•While working in architecture, Charles Rennie Mackintosh developed his own style:
a contrast between strong right angles and floral-inspired decorative motifs with
subtle curves, e.g. the Mackintosh Rose motif, along with some references to
traditional Scottish architecture.
•It, Mackintosh's architectural designs often included extensive specifications for the
detailing, decoration, and furnishing of his buildings.
MURANO
MILLEFIORI PENDANT

SOURCES:
1. Fundamental Building Materials By K. Ward-Harvey
English Heritage , Practical Building Conservation – Glass and
Glazing
2. Research Paper by Dr. Prashant Mehta
Assistant Professor
National Law University, Jodhpur

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