Effect of water incorporation on the diffusion of sodium in an alkaline-earth boroaluminosilicate glass

Tracer diffusion coefficients of sodium ions diffusing in an alkaline-earth boroaluminosilicate glass (Corning Code 1737 glass) were measured by using Na-22 as a radioactive tracer. It was found that the presence of a significant amount of water vapor in the atmosphere surrounding a diffusion sample during diffusion annealing reduces considerably the mobility of sodium in the near-surface region of the glass. This partial immobilization of Na is attributed to an interaction between water dissolved into the glass and diffusing sodium ions.