Chemical Composition of Glass
Glass is an amorphous material, which means that the structure of glass lies between that of a crystalline material and a liquid. Glass is often considered as a super-cooled liquid. At high temperature, glass changes into liquid form where the glass atoms are free to move around. When this liquid glass is cooled down, the atoms rearrange themselves into more efficient packing. However, below a specific temperature, called fictive temperature, atoms do not rearrange themselves. This leads to a short-range order of glass atoms.
The chief raw material used in the manufacture of glass consists of silicon dioxide, limestone, and soda ash.
The primary reason for the popularity of glass is that its properties can be varied according to requirements. The correct combination of raw material and processing technique can be used to yield the desired properties. Glass can be made as strong as steel or more delicate than paper. It can be woven like the web of a spider or it can be molded into a mirror that would weigh in tons. It can be made into a transparent material or given any color.
The properties of glass are governed chiefly by its composition. To manufacture glass, you need the following types of ingredients:
A former forms the base material of any glass. It forms the major percentage in any glass-forming mixture. Silica is the most commonly used former in the glass industry. Other formers include boric acid and phosphoric acid.