FT-IR and UV–Vis optical absorption spectra of γ-irradiated calcium phosphate glasses doped with Cr2O3, V2O5 and Fe2O3

Fourier transform infrared (FT-IR) spectra of xCaO · (100 − x)P2O5 glasses, (mol%) with 45 ⩽ x ⩽ 55, have been studied in order to understand the bonding mechanisms, characteristic frequencies of the vibrational chemical bonds, which are liable to the structural and spectral changes. These spectra showed IR absorption bands related to the characteristic phosphate bonds especially PO, P–O–P, O–P–O, P–O–H and P–O–Ca bonds. UV–Vis spectra of the undoped and doped (with Cr2O3, V2O5 and Fe2O3) glasses have been recorded in the range 200–1000 nm before and after γ-ray irradiation with various doses. The induced absorption spectra, calculated as the difference between the spectra of the irradiated and unirradiated glasses, were used to describe the irradiation induced defects. Intrinsic phosphorus–oxygen related radiation-induced defects, with hole centers POHCs absorbing in the visible region and electron trapped centers PO2- and PO3-ECs absorbing in the ultraviolet region, were found.