What is the main composition of glass and its main function?

Glass is an amorphous inorganic nonmetallic material, which is generally made of a variety of inorganic minerals (such as quartz sand, borax, boric acid, barite, barium carbonate, limestone, feldspar, soda ash, etc.) as the main raw materials, and a small amount of auxiliary raw materials are added. Its main components are silica and other oxides. The chemical composition of ordinary glass is Na2SiO3, CaSiO3, SiO2 or Na2O·CaO·6SiO2, etc. The main component is silicate double salt, which is an amorphous solid with an irregular structure. Widely used in buildings, used to isolate the wind and light, belongs to the mixture. Another mixed with some metal oxides or salts to show the color of colored glass, and through the physical or chemical method of toughened glass and so on. Sometimes some transparent plastics (such as polymethyl methacrylate) are also called plexiglass. The main chemical composition of glass is silicon dioxide and alumina, calcium oxide, magnesium oxide, sodium oxide, potassium oxide, its role is as follows: silicon dioxide is the main component of the formation of glass, and glass has a series of excellent properties, such as transparency, mechanical strength, chemical stability and thermal stability. The disadvantage is that its melting point is high and the viscosity of the molten liquid is large, resulting in melting difficulties and high heat consumption, so other components need to be added to improve this state when producing glass. Adding a small amount of alumina to the glass raw material can reduce the crystallization tendency of the glass, improve the chemical stability and mechanical strength, and improve the thermal stability, but when the content is too much (Al2O3 > 5%), it will increase the viscosity of the glass liquid, making it difficult to melt and clarify, but increase the crystallization tendency, and easy to cause defects such as wave reinforcement on the glass original plate. Adding proper amount of calcium oxide can reduce the viscosity of liquid glass at high temperature and promote the melting and clarification of liquid glass. When the temperature is reduced, the viscosity of the glass liquid can be increased, which is conducive to improving the drawing speed. The disadvantage is that when the content is increased, the crystallization tendency of the glass will be increased, the thermal stability of the glass will be reduced, and the annealing temperature will be increased. The effect of magnesium oxide is similar to that of calcium oxide, but there is no defect that calcium oxide increases the tendency of glass crystallization, so an appropriate amount of magnesium oxide can be used to replace calcium oxide. However, excessive diopside crystallization will occur, increasing the annealing temperature and reducing the stability of the glass to water. Sodium oxide, potassium oxide as a good co-solvent, reduce the annual glass liquid, promote the melting and clarification of glass liquid, but also greatly reduce the glass crystallization tendency, the disadvantage is that it will reduce the chemical stability and mechanical strength of glass.