Sodium tracer diffusion in a sodium aluminosilicate glass

Sodium tracer diffusion coefficients, DNa*, have been measured using the radioactive isotope Na-22 in a commercial, ion exchangeable sodium aluminosilicate glass at different temperatures between about 200 and 400 °C. The activation enthalpy derived from sodium tracer diffusion data for the as-received glass samples was found to be about 75.5 ± 1.2 kJ/mol and the value of the logarithm of pre-exponential factor of the sodium tracer diffusion coefficient, log10[DNa°/(cm2/s)], is − 2.58 ± 0.13. It was observed that pre-annealing the glass samples at the annealing point of 609 °C causes some reduction of the values of the sodium tracer diffusion coefficients. In addition, the glass samples investigated were found to take up water at 300 °C in wet air (PH2OPH2O = 474 mbar). However, an influence of the uptake of water during diffusion-annealing in wet air on the diffusivity of sodium was not observed.

► Diffusion of Na-22 in a commercial sodium aluminosilicate glass studied.
► Temperature dependence of sodium tracer diffusivity investigated.
► Activation enthalpy and pre-exponential factor for sodium tracer diffusion determined.
► Briefly investigated whether take-up of water influences the diffusion of sodium.