The conductivities of type-I and type-IV silica glasses were measured as a function of fictive temperature and water content. Glasses with various fictive temperatures were produced by heat treatment in ambient air, followed by quenching. The water content in the glasses was varied by using high-temperature hydrothermal treatments. It was found that, in the case of type-IV silica glass, the conductivity decreased and the activation energy increased with increasing fictive temperature. These changes appeared to be related to a decrease in the specific volume of the silica glass with increasing fictive temperature. In the case of type-I glass, the changes were much smaller. The changes in water content had various effects upon the conductivities of different types of silica glass. Thus, the conductivity of type-I glass increased slightly, while that of type-IV glass decreased with increasing water content. The opposite trends in these 2 types of glass were attributed to their differing Al contents; which interacted with protons that were introduced by the hydrothermal treatment.

D.W.Shin, M.Tomozawa: Journal of Non-Crystalline Solids, 1996, 203, 262-7