How is tempered glass made (that is, how is it different than regular glass)?
Since you asked this in the engineering section, I’ll give you a real engineering answer! Tempered glass can be made using any type of glass compostition (not just window glass – soda lime silicates). Making a glass consists of heating a glassformer (usually with oher constituents) to melting and then cooling rapidly so the thermodynamic forces (increase in viscocity) overcomes the kenetic desire for the atoms in a liquid state to form an ordered crystal structure. Once a glass is formed, it is allowed to cool as normal before tempering. A non-tempered glass will fail according to Griffith’s criteria, which basically says, once enough energy is supplied to a crack such that the energy at the crack tip exceeds the energy of the bonding at the tip, the crack will propogate. This usually leads to failure in a glass (as with other brittle materials – thermo-set polymers, ceramics) but can just mean your glass cracks. The glass will break wehn the energy needed to create a new surface is in
