Electrical conductivity of gamma-irradiated V2O5 doped lithium disilicate glasses doped and their glass–ceramics derivatives

Some physical properties of the lithium disilicate (Li2Si2O5) glasses doped with different ratios of V2O5 were investigated before and after gamma-rays irradiation. Increasing V2O5 ratio causes remarkable changes in the properties studied. The observed variations in the properties may be correlated with the changes in internal glass network with changes in the chemical composition. Vanadium ions are believed to be present in three possible valence states V3+, V4+ and V5+, and the ratios of these states depend on glass composition.Observed increase in electrical conductivity is assumed to be related to several parameters including the creation of localized state, which increase the charges carrier to conduction band, increase of the number of nonbridging oxygen’s and/ or electron hopping between vanadate ions in different valence states. However, the results indicate that the heat-treatment of amorphous samples accelerate the sequence of formation of lithium metasilicate crystals, causing a decrease in the electrical conductivity. The changes obtained due to gamma-irradiation are correlated to several factors, such as polarization and field strength of the respective cations and to the amount of induced defect centers created upon gamma-irradiation.