Thermal properties and optical transition probabilities of Tm3+ doped TeO2-WO3 glass

Glasses with the composition of (1 - x)TeO2 + (x)WO3, where x = 0.15, 0.25 and 0.3 were prepared and, their thermal and absorption measurements were c arried out. Differential thermal analysis (DTA) curves taken in the 23-600 degreesC temperature range with a heating rate of 10 degreesC/min reveal a change in the value of the glass transition temperature, T-g, while crystal lization was not observed for the glasses containing a WO3 content of more than 15 mol%. All the glasses were found to be moisture-resistant. The abso rption bands corresponding to the absorption of the (1)G(4), F-3(2), F-3(3) and F-3(4), H-3(5), and H-3(4) levels from the H-3(6) ground level of the Tm3+ ion were observed in the optical absorption spectra. Integrated absorp tion cross-sections of each band except that of H-3(5) level was found to v ary with the glass composition. Judd-Ofelt analysis was carried out for the samples doped with 1.0 mol% Tm2O3. The Omega (2) parameter shows the stron gest dependence on the host composition and it increases with the increasin g WO, amount. The value of Omega (4) increases rather slowly while the valu e of Omega (6) is practically independent of the composition. The strong de pendence of the parameter Omega (2) indicates that this parameter is relate d to the structural change and the symmetry of the local environment of the Tm3+ ions in this glass. (C) 2001 Elsevier Science B.V. All rights reserve d.