Electrical Conduction and Dielectric Relaxation in BaO-P<sub>2</sub>O<sub>5</sub> Glasses and their Dependence on Water Content

Abstract

D. c. conductivities and dielectric losses in BaO-P2O5 glasses having various water contents were measured. Water was assumed to be contained in the form of OH group in the glasses as has been shown in our previous works, and its effects on the electrical properties were discussed in terms of proton diffusion in an electrical field;(1) Contrary to the usual alkali free glasses, the BaO-P2O5 glasses showed a clear dielectric dispersion in very low frequency region. Its correlation with d. c. conductivity was similar to that of dispersion of ionic relaxation loss observed in usual alkali containing glasses. The spectral shape was also nearly identical to that for the alkali containing glasses. These facts suggest that the movement of some ions in BaO-P2O5 glasses is responsible for both of d. c. conduction and dielectric relaxation.(2) D. c. conductivities (σ) and magnitudes of dielectric dispersion (Δ ε), which should be closely related to carrier ion concentration, were roughly proportional to the water content. The findings and the acidic nature of OH bond in polymeric phosphates led us to a conclusion that the carrier ion in BaO-P2O5 glasses is a proton.