Vol. 35, Issue 4, pp. 843-850 (2005)

Abstract

Glasses with composition 50 GeO₂–(45 – x)PbO–5 PbF₂–x LnF₃ (Ln = Nd or Sm, x = 0.2 and 2 mol%) were synthesised in the bulk form. Phase profiles and temperature characteristics were measured by differential thermal analysis (DTA); glass transition temperature T_g, as well as the b-PbF₂ T_b and oxide glass crystallisation T_c temperatures have been derived for each individual system. A study of optical properties (absorption, emission) of the PbF₂–Nd³⁺ and PbF₂–Sm³⁺ was carried out. The oscillator strengths were obtained for several optical transitions and they have been used to calculate phenomenological intensity parameters W_{2, 4, 6}. The probabilities of radiative transitions from fluorescent levels of Nd³⁺ and Sm³⁺ ions, as well as branching ratios and radiative lifetimes, were estimated on the basis of the Judd–Ofelt framework. The fluorescence dynamics of studied systems was measured. Experimental lifetimes were compared and discussed with those obtained with the Judd–Ofelt theory.