Gamma-rays interactions on optical, FTIR absorption and ESR spectra of 3d transition metals-doped sodium silicophosphate glasses

Abstract

Glasses of the basic composition mol% 50%P2O5·30%SiO2·20%Na2O together with samples containing one of 3d transition metal oxides (TiO2→CuO) were prepared. Combined optical and FTIR absorption spectra of the prepared glasses were measured before and after gamma irradiation with a dose of 8Mrad (8×104Gy). Undoped sodium phosphosilicate glass reveals strong UV absorption with a peak at 225nm but with no visible bands. Such UV absorption is related to the presence of unavoidable trace iron impurities contaminated with the chemicals used for preparation of this glass. 3d-transition metal ions-doped glasses exhibit characteristic absorption bands extended in the UV/Vis regions which are characteristics for the specific TM ions. Gamma irradiation causes broadness of the UV absorption bands in the spectrum of the undoped glass and the resolution of three peaks at about 250, 310 and 340nm beside the appearance of an induced broad visible band centered at about 450nm. Glasses doped with 3d TM ions reveal variations in their response towards gamma irradiation. FTIR absorption spectra show extended broad vibrational bands which are related to the presence of both vibrational modes due to silicate and phosphate groups but the later groups are predominant due to the high percent of P2O5 (50%). The presence of TM ions within the dopant level (0.2%) causes no obvious changes in the number and position of the IR structural vibrational bands. ESR spectra of 3d TM-ions-doped glasses reveal quite distinct spin resonance after gamma irradiation indicating that unpaired electrons increase through the capturing or releasing of energetic electrons during the irradiation process.