An investigation was made, of the diffusion of H2O molecules in alkali halides, by making K2O additions. The latter reacted with the H2O, changed the color of the crystal, and thereby indicated the depth of water penetration into the halide. It was found that the results, for 180 to 750C, could be described by:

D (cm2/s) = 0.48 exp[-0.56(eV)/kT]

Solubility, Diffusion and Infrared Absorption of Water Molecules in Alkali Halide Crystals. C.Rühenbeck: Zeitschrift für Physik, 1967, 207[5], 446-69