Gas Solubility in Glasses: Principles and Applications

Abstract

There are numerous practical applications of the solubility of gases in glass, for example, gas separation and the outgassing and leak testing of vacuum systems. Analysis of the structure of glass provides an understanding of the mechanisms of gas solution, diffusion, and permeation. The gas atoms (or molecules) serve as structural probes. Noble gas solubility in vitreous silica indicates the distribution of interstitial size to be lognormal in nature, a result confirmed by computer‐generated models. In related studies, computer models have indicated that the ring statistics in vitreous silica are normal (Gaussian) in nature over a wide range of pressures. The geometrical literature on convex polyhedra provides additional detail about the nature of the structure of glass and its relationship to gas transport. This paper focuses on gas solubility in rigid glasses below the glass transition temperature, but there are implications for the related problem of gas solubility in glass melts, another problem of substantial commercial interest. The understanding of gas solubility has also had a significant influence on models of geological importance, such as volcanic eruptions and formation of the earth's atmosphere. These studies in the earth sciences, in turn, enhance our understanding of engineered glasses.