This document discusses glass, including its definition, classification, properties, types, uses, and treatments. It notes that glass is a non-crystalline solid that is transparent and used for practical and decorative purposes. The document classifies the main types of glass as soda lime glass, potash-lime glass, potash-lead glass, and common glass, and describes their properties and uses. It also outlines the main types of glass as annealed, heat strengthened, tempered, and laminated glass. The document concludes with sections on common glass treatments and varieties.

2.  Introduction
 Classification of glass
 Properties of glass
 Types of glass
 Uses of glasS
 Glass treatments
 Varieties of glass

3. About Glass –
 Defination - it is defined as a non-crystalline
amorphous solid that has the property of transparency,
and is used for practical, technological and decorative
purposes.
 Glass is one of the most important materials in usage
and finds many practical applications in our daily lives
and throughout the world.
 Generally, glass is characterised as a transparent solid
material that can be used to make a variety of products
in fields like architecture and design.

4. The glass may be broadly classified as:.
1.Soda Lime Glass This is also known as the soda-glass
or soft-glass. It is mainly a mixture of sodium silicate and
calcium silicate.
Properties:
(i) It is available in clean and clear state.
(ii) It is cheap.
(iii) It is easily fusible at comparatively low temperatures.
(iv) It is possible to blow or to weld articles made from
this glass with the help of simple sources of heat.
Uses:
It is used in the manufacture of glass tubes and other
laboratory apparatus, plate glass, window glass, etc

5. 2.Potash-Lime Glass:
This is also known as the Bohemian-glass or hard-
glass. It is mainly a mixture of potassium silicate
and calcium silicate.
Properties:
(i) It fuses at high temperatures.
(ii) It is not easily affected by water and other
solvents.
(iii) It does not melt so easily.
Uses:
This glass is used in the manufacture of glass
articles which have to withstand high temperatures
such as combustion tubes, etc.

6. 3. Potash-Lead Glass:
This is also known as the flint glass. It is mainly a
mixture of potassium silicate and lead silicate.
Properties:
(i) It fuses very easily.
(ii) It is easily attacked by aqueous solutions.
(iii) It possesses bright lustre and great refractive
power.
(iv) Its specific gravity is about 3 to 3.30.
(v) It turns black and opaque, if it comes into
contact with reducing gases of the furnace during
heating.
Uses:
It is used in the manufacture of artificial gems,
electric bulbs, lenses, prisms, etc.

7. 4) Common Glass:
This is also known as the bottle glass. It is prepared
from cheap raw materials. It is mainly a mixture of
sodium silicate, calcium silicate and iron silicate.
Properties:
(i) It fuses with difficulty.
(ii) It is brown, green or yellow in colour.
(iii) It is easily attacked by acids.
Uses:
It is mainly used in the manufacture of medicine
bottles.

8.  It absorbs, refracts or transmits light. It can be
made transparent or translucent.
 It can take excellent polish.
 It is an excellent electrical insulator.
 It is strong and brittle.
 It can be blown, drawn or pressed.
 It is not affected by atmosphere.
 It has excellent resistance to chemicals.
 It is available in various beautiful colours.
 With the advancement in technology, it is
possible to make glass lighter than cork or
stronger than steel.

9. There are mainly four types of glass
1) Annealed Glass
Annealed glass is a basic product formed from the annealing
stage of the float process. The molten glass is allowed to cool
slowly in a controlled way until it reaches room temperature,
relieving any internal stresses in the glass. Without this controlled
slow cooling, glass would crack with relatively little change in
temperature or slight mechanical shock. Annealed glass is used as
a base product to form more advanced glass types.
2) Heat Strengthened Glass
Heat Strengthened Glass is semi tempered or semi toughened
glass. The heat strengthening process involves heating annealed
glass back up to about 650 to 700 degrees Celsius and then
cooling it quickly, although not as fast as with toughened glass.
The heat strengthening process increases the mechanical and
thermal strength of annealed glass, making it twice as tough as
annealed glass

10. 3) Tempered or Toughened Glass
This is the most common type of glass used in balustrades or
similar structural applications. Annealed glass is heated to about
700 degrees Celsius by conduction, convection and
radiation. The cooling process is accelerated by a uniform and
simultaneous blast of air on both surfaces. The different cooling
rates between the surface and the inside of the glass produces
different physical properties, resulting in compressive stresses in
the surface balanced by tensile stresses in the body of the glass.
4) Laminated Glass
Any one of the above types of glass can be laminated. The most
commonly used finished product is two sheets of toughened
glass, laminated together with a 1.52mm thick Polyvynil Butyral
(PVB) interlayer.

11.  It is used for making furniture items.
 It is used for making windows and doors
 Glass is used for making kitchen utensils
 It is also used for making partitions
 Glass is used to making staircase
 It is also used as a decorative material. Glass is
used as an insulating material

12. ETCHING Normally, glass is transparent.
It can be made opaque mechanically by
grinding the surface by emery. The surface
of the glass can also be made opaque
chemically by the application of hydrofluoric
acid. It is also known as glass etching.
TOUGHENING Glass toughening is the process
of heating and then cooling float glass. This
heating and cooling process alters the chemical
structure of the glass and results in the glass
becoming 5 times stronger and resistant to impact.
BENDING Glass bending is one kind of process
in which, rods, sheets or tubes of glasses are
bent into the desired shape by placing them in
temperature controlled special ovens. They are
heated to suitable temperature then they are taken
out and bent into the desired shape.

13. EDGE POLISHING
Polished edges are produced
by buffing the edge of the
glass with a fine abrasive
material and polishing oil.
FILM APPLICATION
is a thin laminate film that
can be installed to the interior
or exterior of glass surfaces
in automobiles and boats and
also to the interior or exterior
of glass in homes and buildings.

14.  Bullet-proof glass
 Fibre glass
 Foam glass
 Glass blocks
 Heat-excluding glass
 Obscured glass
 Safety glass
 Shielding glass
 Soluble glass
 Structural glass
 Ultra violet glass
 Wired glass