Q. Write an account of soda lime glass and safety glasses.
Ans. Soda-Lime Glass or soft glass: It is the ordinary glass in which Na2O is added to the melt to oxide on heating.
1. Low cost
2. Resistant to devitrification and water
3. Attacked by common reagents like acids
4. Its melts easily
Uses: Soft glass is widely used for (a) Window glasses (b) Electrical bulbs, (c) Plate glasses, (d) Cheaper table wares like bottles, jar etc. (e) Cheap laboratory glassware.
Safety glass or laminated glass: " A glass which when breaks does not allow its broken pieces to fly apart."
Preparation: Safety glass is prepared by placing a thin layer of Vinyl plastic between two sheets of glass. Then the plastic and glass sheets are pressed together under heat, so that the plastic thin layer is sandwiched in between the glass sheets. The edges of the combined sheets are sealed with some water resistant compound. The glass becomes quite tough. (The glass sheets used are ordinary glass sheets and plastic sheet used is of either cellulose acetate of polyvinyl butyl (acetyl) resin).
(1) Safety glass shatter-proof.
(2) It is quite touch.
(a) Three layer laminated glass is used as wind shields in automobile and aeroplane industries.
(b) Five-layer laminated glass is used in building construction.
(c) Several layer laminated glass is bullet proof and used for making looking windows, automobile wind screens.