EPR of γ-induced paramagnetic centers in tellurite glasses

Intrinsic paramagnetic responses were observed in the 60TeO2–25ZnO–15Na2O and 85TeO2–15Na2O mol% glasses, after γ-irradiation at room temperature: (1) a shoulder at g1 = g∥ = 2.02 ± 0.01 and an estimated g⊥ ~ 2.0 attributed to tellurium–oxygen hole center (TeOHC); (2) a narrow resonance at g2 = 1.9960 ± 0.0005 related to the modifiers and (3) a resolved resonance at g3 = 1.9700 ± 0.0005 ascribed to a tellurium electron center (TeEC) of an electron trapped at an oxygen vacancy (VO+) in a tellurium oxide structural center. It is suggested that the creation of (NBO−,VO+) pair follows a mechanism where the modifier oxide molecule actuates as a catalyser. An additional model for the NBO radiolysis produced by the γ-irradiation is proposed on the basis of the evolution of the g1, g2 and g3 intensities with increasing dose (kGy).