UV-vis absorption of the transition metal-doped SiO2–B2O3–Na2O glasses

Ultravoilet (UV)–vis absorption spectra of undoped and transition metal (TM)-doped borosilicate glasses before and after successive gamma rays irradiation are reported. Before irradiation, the undoped glass reveals UV absorption due to trace iron impurities and no visible bands whereas the TM-doped glasses show the absorption bands which are characteristic for each TM ion in the UV and visible regions. The induced absorption bands are examined and related to either intrinsic radiation-induced defects from the host base borosilicate glass or extrinsic induced defects generated from TMs. The response of the glasses to gamma irradiation is related to the creation of defect color centers, the approach of a saturation condition and/or the possible photochemical effect on TM.