Reducing Power of Phosphate Matrix in Binary Barium Phosphate Glasses Doped with 3d Transition Metals and Effects of Gamma Radiation

Spectroscopic characterization was performed for base and first row transition metal ions (3d TM) doped barium metaphosphate glasses. The procedure was conducted using FTIR and optical spectral measurements before and after 8 M rad gamma irradiation. Electronic spectra show distinct UV absorption with a peak around 230 nm in nearly all samples correlated with trace iron ions present as an impurity within the chemicals used for the preparation of the glasses. 3d TM ions-doped samples exhibit additional characteristic bands mainly in the visible due to each respective TM ion. Such optical spectra indicate and support the assumption that the host phosphate glass generally promotes the reduced state or octahedral coordination of the TM ions to a measurable extent. Gamma irradiation produces mostly an extension of the UV spectra and this effect is correlated with the assumption of photochemical reactions of the trace iron ions impurities during the irradiation process in which some ferrous ions capture positive holes and are transformed to additional ferric ions causing the extension. FTIR absorption spectra reveal vibrational bands due mainly to metaphosphate groups and the P-O-P mode while TM ions doped glasses show no distinct variations due to the stability of the phosphate network containing high content of heavy Ba 2+ ions and the presence of TM ions in low doping percent.