MOSSBAUER-EFFECT STUDY OF THE EFFECT OF GAMMA-IRRADIATION ON THE BEHAVIOR OF IRON IN SODIUM-SILICATE GLASSES

The effect of gamma irradiation on the behaviour of iron in a sodium s ilicate glass system [40 mol% SiO2, 60 mol% Na2O and 1-6 mol% Fe2O3] w as investigated by Mossbauer effect (ME) and electron spin resonance ( ESR) techniques. The changes in the quadrupole splitting (QS), line wi dth of the ME spectra and the intensity of the g = 4.2 absorption line of the ESR spectra, showed that the distribution of the charges aroun d the Fe nucleus became more symmetrical and less distorted than befor e irradiation. The change in the Fe-0 interatomic distance due to gamm a irradiation was determined using the overlap contribution to isomer shift (IS) for the Fe3+ ion in both tetrahedral and octahedral sites. The aging effect on the relaxation time of the electric field gradient (EFG) at the iron nucleus in irradiated glass showed that the relaxat ion time is increased and after certain period recombination of the de fects occurred.