Intrinsic strength and the structure of glass

Intrinsic strength is the strength of a glass without extrinsic flaws. Knowledge of the composition dependence of the intrinsic strength is important both technologically for the development of high strength glass compositions and theoretically as it may provide important structural information. Intrinsic strength is easy to define but difficult to measure experimentally. In this paper we discuss intrinsic (σ*) strength measured in normal laboratory conditions as well as the inert intrinsic (σ0*) strength. We define these terms in a rigorous manner and indicate how to gauge if they have been measured by developing a set of criteria. Based on these criteria, we tabulate those values of intrinsic strengths that have been measured to date.