Effects of fast neutron and gamma irradiation on electrical conductivity of some borate glasses

Electrical conductivity of samples of Li2O-B2O3 binary glass system containing Al2O3, PbO, FeO3, TiO2 or V2O5 was measured at temperatures ranging between 30 and 200 degreesC before and after irradiation with fast neutrons or gamma-rays. Base and Al2O3-containing glasses showed an initial rise in conductivity with the increasing temperature. followed by a steep drop. then a more gradual increase. Glass samples containing lead or one of the transition metal oxides showed a linear pattern of electrical conductivity in response to heating. In these glasses activation energy varied depending on the coordination number of the transition metal ion involved. These changes in electrical conductivity in response to temperature are ascribed to changes in the internal structure of the lithium borate glass, which is also affected by the presence of aluminum, lead or transition metals. The effects of exposing the studied glasses to irradiation were attributed to irradiation-induced changes in the configuration of the glass network. including the formation of matrix defects. (C) 2002 Published by Elsevier Science B.V.