Published online by Cambridge University Press: 31 January 2011
We report on the relaxation of ultraviolet-radiation-induced structure and long-lasting phosphorescence in Eu2+-doped glass samples with compositions of xAl2O3 · 40SrO · (60 − x)SiO2· 0.05Eu2O2 · 0.05Dy2O3 (x = 0, 10, 30) (mol%). After irradiation by an ultraviolet lamp (λmax = 254nm) with a power density of 5 mW/cm2 for 30 min, a visible light (peaking at 510 nm) could be seen with the unaided eye in the dark even 24 h after the removal of the activating light. Thermostimulated luminescence glow curves, x-ray absorption, and electron-spin-resonance spectra were measured. We suggest that the long-lasting phosphorescence in the Eu2+-doped glass samples resulted from the recombination of electrons and holes at shallow traps in the glass matrix that can be thermally released at room temperature, and energy transfer between the recombination centers and Eu2+ ions.