Glass: Structure Without Crystals
Understand glass formation, viscosity, thermal history and brittle fracture.
An amorphous solid
Glass lacks long-range crystalline order but has local structural motifs. Its properties depend on composition and frozen-in structure.
The glass transition
Cooling increases viscosity until structural rearrangement becomes too slow. The apparent transition depends on thermal history and rate.
Residual stress
Non-uniform cooling creates stress. Annealing relieves it; tempering deliberately creates surface compression to improve strength.
Failure and flaws
Glass is strong in principle but surface flaws govern fracture. Chemical attack and handling damage reduce reliability.
Engineering takeaway
Control surface condition, edge quality and thermal stress; nominal composition alone does not determine strength.