Temperature dependence of silver-sodium interdiffusion in micro-optic glasses

The variation of the concentration-dependent diffusion process with ion exchange temperature from 280°C to 400°C has been investigated in two boro-aluminosilicate glasses suitable for micro-optic applications. Silver dopant concentration profiles are measured using energy dispersive X-ray spectroscopy and converted to concentration dependence using an analytical formulation of the Boltzmann-Matano analysis. Extensive error analysis of the Boltzmann-Matano method is presented. While the overall interdiffusion rates vary strongly with temperature, the temperature variation of the concentration dependence does not exceed experimental error. Temperature dependencies of Ag and Na self-diffusion coefficients are also presented. The activation energies for Ag and Na are both approximately 0.72 eV in these glasses.