Concentration dependence of water diffusion in silicate glasses

Abstract

Diffusion experiments of water in SiO₂ glass were made to understand the concentration dependence of water diffusion and its mechanism. We propose that water diffusivity in SiO₂ glass is controlled by the relative abundance of main diffusion species (molecular water) and numbers of diffusion pathways, which are produced by hydroxyls. Our model is applicable to water diffusion in silicate glasses by considering the effects of concentration of network modifier cations and the water concentration dependence of activation energy.