Silica glass fluxed with sodium and calcium oxides, making up about 90% of all manufactured glass.
Core Principles & Analysis
A typical composition is about 72% silica, 14% sodium oxide, and 10% lime; the soda flux sharply lowers the melting temperature while lime restores chemical durability.
Nearly all flat window glass is made by the float process, invented by Pilkington in the 1950s, in which molten glass spreads over a bath of molten tin.
Thermal tempering locks the surface in compression so the glass shatters into small blunt granules, which is why it is used for car side windows.