Ion transport in hydrated sodium silicates (water glasses) of varying water content

Ionic conductivities in hydrated sodium silicate gels (water glasses) of SiO2/Na2O 3.41:1 mole ratio have been obtained by impedance spectroscopy at temperatures above and below the thermally determined glass transition temperature. Conductivities at Tg are in the range 10−6 to 10−7 S cm−1, which are similar to those found recently in several kinds of polymer electrolyte. It is suggested that the absence of a mixed alkali effect and a strong dependence on water imply that conductivities are largely protonic in nature and involve strong interactions between protons, water molecules and the silicate framework.