Effect of melting condition on optical, FTIR and E.S.R properties of irradiated fluorophosphate glasses containing vanadium ions

Glasses from the system Na2O–CaF2–P2O5 with varying doping V2O5 (0.5, 0.75, 1%) were prepared under ordinary and reducing conditions. Multiple Characterizations including optical, FTIR and ESR spectral data were obtained for the prepared glasses before and after gamma irradiation (with a dose of 6 Mrad).Optical absorption spectrum of the undoped sample reveals strong and broad UV absorption with two peaks which are related to unavoidable traces of iron (Fe3+) ions contaminated within the chemicals used for the preparation of the glasses. The V2O5 doped glasses show two additional pronounced broad visible and near-IR bands which varied in intensity and position of their peaks with the V2O5 content and condition of melting. These distinct visible and near IR bands are assumed to be indicator for the presence for low valence trivalent and tetravalent vanadium ions with variable percents, in accordance with the included host fluoro-phosphate glass and different melting conditions. Gamma irradiation causes noticeable effect on the optical spectrum of the undoped glass but the spectra of V2O5-doped samples reveal pronounced shielding behavior. FTIR spectra of the prepared glasses show distinct vibrational bands due to asymmetric and symmetric vibrations of the phosphate groups of main (PO4) groups and together with the presence of some (PO3F) groups. The detailed FTIR spectra show minor variations with the V2O5 content or condition of melting. E.S.R results show distinct signals due to the presence of both trivalent and tetravalent vanadium ions which possess unpaired electrons in their outer electronic configurations. E.S.R data reveal limited variations in the intensity of the signals with varying V2O5 content or condition of melting and even upon gamma irradiation points out to the stability of V3+ and V4+ ions in the studied host fluorophosphate glass.