Difference in radiation effects of sodium borosilicate glass and vitreous silica with ions

Borosilicate glass is used to vitrify high-level radioactive waste. Radiation effects on borosilicate glass have been studied extensively. Sodium borosilicate glass samples with compositions of 67.3% SiO2, 16.7% B2O3 and 16% Na2O in molar percent and vitreous silica were irradiated with multi-energy and single-energy Xe ions. After irradiation, hardness and modulus of both materials were accessed by nanoindentation. Volume change in two materials was evaluated using AFM. The hardness, modulus and volume change of both sodium borosilicate glass and vitreous silica varied fast and then saturated with the dose. The trends of both modulus and volume change with the dose for sodium borosilicate glass were respectively opposite to those for vitreous silica. The relative hardness variation of sodium borosilicate glass was −35%, and that of vitreous silica was about −10%. Difference in radiation effects between the sodium borosilicate glass and vitreous silica suggested that hardness decrease in sodium borosilicate glass irradiated with ion might be induced not only by transformation of silicate network but also by the transformation of boron network.