A glass is an amorphous solid whose structure lacks the long-range periodic order of a crystal. Window glass is a silicate-based example, but glass formation is not restricted to one chemical composition.
Cooling and relaxation history affect structure and residual stress. The glass transition concerns the slowing of molecular or atomic rearrangements, so it differs from the equilibrium melting of an ideal crystalline phase.
Formation of compositionally distinct regions in a glass. A minor, less durable region can change release behaviour even when the bulk composition is unchanged.
Formation of crystalline regions from an initially glassy material. Its effect on waste-form durability depends on the phases formed and the composition left in the residual glass.
A constituent that changes network connectivity or charge balance. Alkali ions can be exchanged during aqueous glass alteration without initially releasing the entire silicate network.
A constituent participating in the connected glass network. silicon and boron can be network formers in borosilicate waste glass; local coordination depends on composition.
A glass containing boron- and silicon-based network formers. Waste-glass durability depends on the full composition and contacting solution, not solely on the presence of these two elements.
A kinetic crossover at which structural or segmental relaxation becomes too slow for the observation timescale. Its apparent temperature depends on thermal history and measurement rate.
The empirical relation for some homogeneous polymer mixtures or copolymers, with temperatures in kelvin and mass fractions .
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Glass is a state of matter, characterizing amorphous solids. The structure of glass neither exactly resembles that of a crystalline solid nor that of a liquid.
Glass is a solid material that is typically transparent or translucent, made by heating a mixture of silica (sand), soda (sodium carbonate), and lime (calcium oxide) to high temperatures until it melts and then allowing it to cool into a rigid structure. The cooling process does not allow for the formation of a crystalline structure, which is why glass is classified as an amorphous solid. The properties of glass can vary widely based on its composition and the treatment it undergoes.
