Water diffusion and solubility in alkali germanate melts

Water diffusion and solubility have been measured in sodium and potassium germanate melts at 1100degreesC and 1/4 atm partial pressure of water vapour: The diffusivity of water in these melts, which increases with increasing alkali content, is related to the structure of the melt. Water solubility is higher in melts containing soda than in those containing potash. Infrared spectra of water in these glasses can be interpreted using a structural model for alkali germanate glasses. The effect of water concentration on the glass transformation temperature of alkali germanate glasses is related to the fragility of the melt. A nets method for estimating the integrated extinction coefficient for water in glasses is presented.