ABSORPTION AND FLUORESCENCE OF Sm^{3 +} IN GeO₂, AND TERNARY GERMANATE GLASSES.

Absorption spectra of Sm**3** plus were measured in GeO//2, ternary germanate glasses and borax in the spectral range 6000 - 30,000 cm** minus **1. Oscillator strengths of f-f transitions of Sm**3** plus in these media were calculated. Fluorescence spectra and decay times arising from the transition of the **4G//5/////2 level were measured and the quantum efficiencies calculated. It was found that these values are higher by a factor of twenty in the ternary germanate glasses compared to GeO//2. This fact is explained by the cross relaxation between neighboring Sm**3** plus ions, which is higher in GeO//2. A discussion on the influence of glass phonons on cross relaxation processes, is given.