As present, it is possible to alter the chemical, electrical, mechanical and optical properties of glass by suitably changing the basic composition of the glass. As a matter of fact, the glass has emerged as a versatile engineering material which can be tailor-made to meet with the requirements of different industries in the most effective and economic way.
The brief descriptions of some of the following important special varietites of glass are given:
(1) Bullet-proof glass
(2) Fibre glass
(3) Float glass
(4) Foam glass
(5) Glass blocks
(6) Heat-excluding glass
(7) Obscured glass
(8) Perforated glass
(9) Safety glass
(10) Shielding glass
(11) Soluble glass
(12) Structural glass
(13) Ultra-violet ray glass
(14) Wired glass.
(1) Bullet-proof glass: This glass is made of several layers of plate glass and alternate layers consist of vinyl-resin plastic. The outer layers of plate glass are made thinner than the inner layers. The special care is to be taken for heating and cooling of layers during manufacture. The thickness of this type of glass may vary from 15 mm to 75 mm or more. It will not allow bullet to pierce through it.
(2) Fibre glass: The fibre glass is composed of minute glass rods and each glass rod resembles the parent material in all respects. It is soft to the touch and it is flexible in nature. It does not absorb water and it is proof against fire, vermin’s, water and acids. It can be prepared either I the form of continuous stands just like silk or in the staple form just like wool.
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