LONG-LASTING PHOSPHORESCENCE IN EU2-DOPED CALCIUM ALUMINOBORATE GLASSES()

We report on the long lasting phosphorescence phenomenon in Eu (2+)-do ped glasses based on CaO-Al2O3-B2O3. After irradiation by a white-colo r fluorescent lamp with a power density of 2 x 10(4) Ix for 30 min, th e glass samples emit a visible light peaking at 510 nm which can be se en with the naked eye in the dark even 8 h after the removal of the ac tivating light. Based on the X-ray absorption spectra, the long lastin g phosphorescence in the Eu2+-doped glasses is considered to result fr om the recombination of electrons and holes at shallow traps in the gl ass matrix which can be thermally released at room temperature. (C) 19 98 Elsevier Science Ltd. All rights reserved.