The self-diffusion of Na was studied, below the glass transition temperature, in ZrF4–BaF2–LaF3–NaF glasses with NaF contents of 10, 20 or 30mol%. It was found that the self-diffusivities ranged from 10-12 to 10-14cm2/s, and fell exponentially with increasing NaF content. It was noted that, in order to obtain precise diffusion data, it was essential to achieve the anhydrous deposition of the 22Na radioactive tracer on the highly reactive glass surfaces.

Sodium Self-Diffusion in Some Heavy Metal Fluoride Glasses. A.Buksak, G.H.Frischat: Journal of Non-Crystalline Solids, 2003, 326-327, 68-71