BASICITY VARIATION IN NETWORK OXIDES - DISTRIBUTION OF METAL-ION SITES IN BORATE GLASS SYSTEMS

Ultraviolet probe ion and far-infrared spectroscopic results for bariu m berate glasses indicate the existence of two types of cation-hosting site differing in electron density, that is, basicity. The pattern is similar to the sodium berate glass system, which has the same average theoretical optical basicity trend. However, the basicity span for th e bipositive ions is less than for the monopositive, and this is expla ined in terms of the partial charge neutralization effected by the oxi de(-II)/metal ion interaction, roughly in accordance with Pauling's el ectroneutrality principle. The results explain abnormal optical basici ty values reported previously for studies involving electrolysis of gl ass and the effect of temperature.