Mossbauer Studies and Gamma Irradiation Effects on Some Physicochemical Properties of Borophosphate Glasses Doped with Iron Oxide

A series of high iron content boro-phosphate glasses having composition of 30P(2)O(5)-70B(2)O(3)-xFe(2)O(3));0 <= x <= 80 wt% was prepared by conventional melt quench method. Mossbauer effect (ME), infrared (IR) and electron spin resonance (ESR) were used to study the behavior of iron brought into borophosphate glass and its effect on the structure of the glass. The results of the glasses containing from 10 to 80 wt% Fe2O3 indicated that iron is present in the glass in the form of Fe3+ and Fe2+, i.e. in tetrahedral and various octahedral symmetric sites. Electron paramagnetic resonance (EPR) spectra were utilized to investigate the glass structure. The analysis shows a well-defined signal at g = 2.04 characteristics for Fe3+ ions and the intensity increases with increasing Fe2O3 concentration before gamma irradiation. After exposing the samples to different doses of gamma irradiation up to 30 kGy; the EPR signal intensity decreases for the samples with a low Fe2O3 concentration (i.e. 10% and 40%), which can be used as radiation indicators. For glass with high iron concentrations above 40%, the intensity of the EPR signal remains approximately constant and therefore, high iron concentrations of this glass can be used for radiation protection purposes.