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 → 7F2 to 5D0 → 7F1 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, Ω2, with composition depended on the structural change in the vicinity of Eu3+ ions and EuO covalency.