Time-resolved fluorescence measurements on Dy3+ and Sm3+ doped glasses

Various fluoride, phosphate and borosilicate glasses with known properties and global structure have been doped with Dy3+ (4f(9)) and Sm3+ (4f(5)) between 10(18) and 10(21) cm(-3) and their time resolved fluorescence in the visible range in combination with characteristic physical properties were studied. Different fit procedures were carried out. Although both ions differ in their intrinsic fluorescence lifetime, with 1.5 ms for Dy3+ and 6.5 ms for Sm3+ their dependence on glass matrix is remarkable similar. Fluoroaluminate glasses with varying phosphate content between 0 and 20 mol% (FPx), a pure phosphate glass (P100), and two borosilicate glasses with low (DURAN(R)-like) and high optical basicity (NBS1) were used for investigations. A strongly ionic surrounding by fluorine ligands, as in fluoroaluminate glass samples, provides the longest fluorescence lifetime. It decreases with increasing phosphate content by increasing oxygen surrounding and with increasing RE3+ doping. Large differences were detected in the two borosilicate glasses depending on their optical basicity mainly due to differences in the Na2O/B2O3 ratio. Duran-like samples with low Na2O content have shown phase separation with higher doping concentration. The RE3+ ions are accumulated in the borate-rich droplets. Surprisingly only very low concentration-quenching effects were observed. In the opposite of NBS1 samples with high Na2O content this generated extremely high quenching effect. (C) 2007 Elsevier B.V. All rights reserved.