EFFECT OF MODIFIER IONS ON FLUORESCENCE AND ABSORPTION OF EU3+ IN ALKALI AND ALKALINE-EARTH SILICATE-GLASSES

Fluorescence and absorption spectra of Eu3+ in silicate glasses have been measured. The fluorescence intensity ratio of 5D0 --> F-7(2) to 5D0 --> F-7(1) transitions of Eu3+ increases with increasing ionic radius in the order of Li < Na < K for binary alkali silicate glasses and with decreasing ionic radius in the order of Ba < Sr < Ca for binary alkaline earth silicate glasses. It was found for the first time that the intensity ratio exhibited a maximum with the addition of alkaline earth oxides in alkali alkaline earth silicate glasses. The variation of intensity ratio and the Judd-Ofelt parameter, OMEGA2, with composition depended on the structural change in the vicinity of Eu3+ ions and Eu-O covalency.