EPR of γ-induced paramagnetic centers in tellurite glasses

Abstract Intrinsic paramagnetic responses were observed in the 60TeO 2 –25ZnO–15Na 2 O and 85TeO 2 –15Na 2 O mol% glasses, after γ-irradiation at room temperature: (1) a shoulder at g 1 = g ∥ = 2.02 ± 0.01 and an estimated g ⊥ ~ 2.0 attributed to tellurium–oxygen hole center (TeOHC); (2) a narrow resonance at g 2 = 1.9960 ± 0.0005 related to the modifiers and (3) a resolved resonance at g 3 = 1.9700 ± 0.0005 ascribed to a tellurium electron center (TeEC) of an electron trapped at an oxygen vacancy (V O + ) in a tellurium oxide structural center. It is suggested that the creation of (NBO − ,V O + ) 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 g 1 , g 2 and g 3 intensities with increasing dose (kGy).