Effect of gamma radiation and thermal treatment on some physical properties of ZnO-PbO-B₂O₃ glasses

The microhardness H_v of xZnO.(50-x)PbO.50B₂O₃ glasses has been studied as a function of ZnO content and gamma dose. H_v shows a maximum at about 15 mol.% ZnO. ¹¹B NMR suggests the formation of non-bridging oxygen ions in the borate network as ZnO is added in the PbO.B₂O₃ glass. Both the density and the molar volume decrease with the increase of ZnO. Irradiation with gamma rays lowers the microhardness, whereas heat treatment causes its increase. Infrared investigations indicate that radiation induced defects can activate phase separation processes when the irradiated glass is heat treated.