Comparison of electrical conductivity and thermal properties of borosilicate glass with and without simulated radioactive waste

Abstract

Electrical conductivity and percentage linear thermal expansion of the borosilicate glass (BSG) and simulated waste-loaded borosilicate glass (BSGW) were measured in the temperature range of 300–780 K and compared. Pronounced increase in electrical conductivity was observed around glass transition temperature (T g) of BSG and BSGW. The activation energy (E a) of electrical conduction determined from the measured data for BSG and BSGW is 0.961 ± 0.005 and 0.960 ± 0.005 eV, respectively. The % average linear thermal expansion of BSGW showed a slight decreasing trend compared with pristine BSG. The average coefficient of thermal expansion determined from dilatometry data is 12.87 ± 0.24 × 10−6 and 11.94 ± 0.23 × 10−6 K−1 for BSG and BSGW, respectively. The T g measured by dilatometry is 806 ± 24 K for BSG and 790 ± 23 K for BSGW, respectively. The T g measured by DTA was found to be 820 ± 7 and 805 ± 5 K for BSG and BSGW, respectively, for heating cycle. The T g values obtained from DSC measurements are 805 ± 5 and 803 ± 5 K for BSG and BSGW, respectively. The T g of BSGW showed a slight decrease compared with that of BSG. The values obtained by DSC examination also showed the lowering of T g values for the waste-loaded composition. The lowering of T g may be attributed to the interaction of glass-forming agents and simulated waste elements.