Luminescence properties of Pr3+ doped Li2O-MO-B2O3 glasses

Lithium borate glasses of composition 30Li2O-10MO-59B2O3:1Pr2O3 (MO=ZnO, CaO and CdO) were prepared by a conventional melt quenching method. The amorphous nature of these glasses was confirmed by X-ray diffraction. Characterization of these glasses was carried out by differential scanning calorimetry and infrared spectra. Optical absorption and photoluminescence spectra of these glasses were investigated. Judd-Ofelt intensity parameters Ωλ (λ=2, 4, and 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. From this theory various radiative properties like transition probability A, branching ratio βr, the radiative lifetime τR, and the stimulated emission cross-section σP for various emission levels of these glasses have been determined and reported. The relationship between the structural modifications and luminescence efficiencies of all the three glasses is explained. After X-ray irradiation on these glasses, the thermoluminescence emission properties were also studied. The thermoluminescence studies indicate that CdO modified glass gives out the maximum thermoluminescence light output among the three glasses studied.