FLUORESCENCE PROPERTIES OF SM2-GLASSES( IONS IN SILICATE)

The fluorescence properties of Sm2+ ions incorporated in silicate glas ses were investigated using steady-state and laser-induced line narrow ing techniques. Sm2+ ions were incorporated in the glass matrix by hea ting the Sm3+ ion-containing glasses in H-2 gas. The reaction of Sm3into Sm2+ was accelerated with increasing temperature. The fluorescenc e intensity of the Sm2+ ions increased with heating to 800 degrees C. Further heating above 900 degrees C precipitated mullite crystals. Acc ordingly, the fluorescence intensity of the Sm2+ ions abruptly decreas ed and the fluorescence of Sm3+ ions again appeared. Sm2+ ions are pre ferentially coordinated with Al-O polyhedrons. The crystallization of mullite induces the decrease in Al2O3 content in the remaining glassy phase, resulting in the redox equilibrium producing the high valence s amarium ion. Three Stark splitting fluorescence peaks of the D-5(0) -- > F-7(1) transition were analyzed to determine the parameters of the c rystal field surrounding the Sm2+ ion. The decrease in the number of A l-O bonds surrounding Sm2+ causes the Sm2+ ions' coordination number t o decrease with the short distance of the Sm-O bonds. (C) 1996 America n Institute of Physics.