  Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectra
(XPS) of Nd doped phosphate glasses have been studied before and after gamma
irradiation in order to find the behavior of chemical bonds, which decide the
structural changes in the glass samples. IR absorption spectra of these glasses
are found dominated mainly by the characteristics phosphate groups, water (OH)
present in the glass network as well as on the composition of glass matrix. The
effects of gamma irradiation are observed in the form of bond breaking and
possible re-arrangement of the bonding in the glass. Energy dispersive X-ray
spectroscopy (EDX) and XPS measurements show changes in the relative
concentration of elements; particularly decrease in the concentration of oxygen
in the glass samples after gamma irradiation, a possible source of oxygen
vacancies. The decrease in the asymmetry in O 1s spectra after gamma
irradiation indicates towards decrease in the concentration of bridging oxygen
as a result of P-O-P bond breaking. Asymmetric profile of Nd 3d5/2peak after
gamma irradiation is found to be due to conversion of Nd3+ to Nd2+ in the glass
matrix.
