| Summary: | The effects of γ-ray irradiation (10, 100 kGy) on Gd3+-doped phosphate glass were evaluated. Glass irradiated at 100 kGy was characterized alongside the pristine by differential scanning calorimetry, Fourier transform-infrared spectroscopy and Raman scattering, wherein a lack of alteration in thermal and structural properties was supported. Yet, absorption bands developed around 500 nm with γ-ray dose indicating phosphorus oxygen hole center defects. Optical band gap and Urbach energies exhibited decreasing and increasing trends, respectively, reflecting the influence of trapped electrons and increased disorder/defects. By exciting γ-irradiated samples at 265 nm, blue radio-photoluminescence was observed where intensity increased with dose. Decay curves measured monitoring 415 nm emission showed first-order kinetics suggested to arise from phosphorus electron centers. Emission from Gd3+ was quenched with gamma-ray dose while the 6P7/2 emitting state lifetimes decreased. Correlations between Gd3+ emission intensities and lifetimes with optical band gaps suggest electron center defects perform as ‘energy sinks’.
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