Question

What is meant by annealing of glass? Name the four types of glass. Write anyone's use of every type of glass.

Answer 1

Hint: Heat treatment of glass is the process used to alter the physical or chemical properties of glass. It includes annealing, tempering, case hardening, etc. It is a group of metal and industrial working processes used to make changes in glass properties.

Complete step by step answer:
Annealing is a heat treatment process in which glass cools from the forming range to room temperature. It causes thermal stresses that adversely affect the strength properties. It is done to eliminate thermal stress. It involves heating the glass to annealing range and holding it there for a while and then cooling it slowly to room temperature.
Glass is a hard, amorphous, brittle, and transparent or translucent supercooled liquid of infinite viscosity and having no definite melting point. It is unaffected by air, water, acid or chemical reagents. It can absorb, transmit, and reflect light.
Types of glass are:
1.Soda-lime
2.Lead glass
3.Pyrex
4.Safety glass
Soda-lime – low cost, resistant to water but not to acids. Its composition is silica, calcium carbonate, and soda ash. It is used to make electric bulbs, window glass, test tubes, jars, etc.
Lead glass–bright lustrous and have high specific gravity. Its composition is $K_{2}C{o}_3.PbO.Si{O}_2$ . It is used to make high-quality tableware, optical lenses, cut glass, and windows to protect from gamma rays, X-rays, etc.
Pyrex – It is used to form kitchen wares, chemical plants, and television tubes and is used for a pipeline of corrosive liquids.
Safety glass- it is used as a windshield in airplanes or automobiles.

Note:
Heat Treatment of glass is necessary to increase its strength to resist external stresses like stress, thermal load, or snow loads caused by the sun’s energy. It helps to fulfill the safety requirements by applying federal standards or codes.