Impact effect of gamma irradiation on the optical, FTIR, ESR spectral properties and thermal behavior of some mixed (PbO + Bi2O3) borate glasses searching for shielding effects

Abstract

Four borate glasses with mixed and equal heavy metal oxides PbO+Bi2O3 ranging from 70→55% were prepared by routine melting and annealing technique. These glasses were selected to identify the effects of gamma irradiation on glasses combining two heavy metal oxides (PbO, and Bi2O3) which are known to be of shielding nature towards irradiation. Collective measurements of the optical, structural FTIR and ESR. spectral properties of the prepared equal mixed glasses were carried out before and after a relatively high dose of gamma rays (6 M rad). Optical spectra of the glasses reveal before irradiation strong UV absorption due to trace ferric ions present as impurities in the chemicals used for the preparation of the glasses. After irradiation, an extra small induced near-visible band at 420 nm has been identified and is attributed to the creation of an induced boron- oxygen hole center (BOHC) or nonbridging oxygen hole center (NBOHC). FTIR spectra reveal distinct vibrational bands due to triangular (BO3 groups) and tetrahedral (BO4 groups) within their variant characteristic wavenumbers. Also, the condensed intensities of the FTIR bands refer to the sharing of vibrations due to PbO or BiO within their specific sites as evidenced by the deconvoluted spectra. Gamma irradiation causes no variations on the FTIR and ESR spectra confirming the shielding effect of the heavy metal oxides present in mixed percentages.