Helium Diffusion and Solubility in K ₂ O‐SiO ₂ Glasses

Abstract

Helium permeation, diffusion, and solubility were measured for K 2 O‐SiO 2 glasses containing 0 to 32 mol% K 2 O. All 3 parameters decrease continuously with increasing K concentration. Comparison of these results with those reported previously for Na 2 O‐SiO 2 glasses confirm the contention that helium migration in glass is affected by changes in substructure as well as in atomistic structure. Helium mobility and solubility in single‐phase glasses appear to be controlled by the accessible free volume of the glass network.