Effect of glass composition on diffusion of cesium in borosilicate glass

Heavy ion Rutherford backscattering spectrometry, with 30MeV 19 F beam, has been used to study the diffusion of cesium in borosilicate glasses of different compositions. The coefficient of cesium diffusion in borosilicate glass was obtained by analyzing the depth profile of cesium in samples annealed at different temperatures in the range of 100-350°C. The activation energy of diffusion of cesium was found to be in the range of 9-22kJ/mol, indicating the inter-diffusion between the cesium and sodium as the mechanism of the diffusion process. The activation energy was found to decrease with increasing sodium content of the glass, indicating that the alkali metal ion diffusion is governed by the interaction between the jumping ion and the dipole field around the oxygen ions.