The upper faces of float-glass samples were exposed to vapor, resulting from the decomposition of KNO3 at 565C, for up to 32h. The X-ray dispersive spectra showed that K+ ions migrated into the glass. The K+ concentration profile was obtained, and its diffusion coefficient was calculated by using the Boltzmann–Matano technique. The mean diffusion coefficient was about 10−10cm2/s. It was observed that the refractive index and the Vickers hardness decreased with depth, and their profiles were thus obtained. These profiles permitted the calculation of the diffusion coefficient of K+ via the Boltzmann–Matano technique; giving mean results ranging from 6 x 10−11 to 3 x 10−10cm2/s.

Diffusion Coefficient of K+ in Ion Exchanged Glasses Calculated from the Refractive Index and the Vickers Hardness Profiles. B.Z.Saggioro, E.C.Ziemath: Journal of Non-Crystalline Solids, 2006, 352[32-35], 3567-71