Composition-structure-property relation of oxide glasses: insight from an extended topological approach

The composition of glass can be varied continuously within their glass-forming
regions. This compositional flexibility makes it possible to tailor the
properties of a glass for a variety of specific uses. In the industry such tailoring
is done on a trial-and-error basis with only the intuition of a glass scientist
to suggest a way forward.
To a first approximation the intuition of the glass scientist boils down to two
ideas: First, a higher degree of polymerization causes an increase in physical
properties such as the glass transition temperature and hardness. Second, a
higher oxygen bond strength also increases such properties. Yet, these rules
are not strictly followed even for the simplest binary oxide glasses, such as
alkali silicates, borates and phosphates.
In this thesis it is argued that the missing link between composition and properties
is the glass structure. Structural models are proposed based on topological
selection rules and experimentally verified. The relation between structure
and properties is evaluated using topological constraint theory, which in
its essence is a theory that quantifies the two intuitions of the glass scientist.
The end result is a quantitative model capable of ab initio prediction of the
oxide glass properties from composition.