FTIR and UV–VIS spectroscopy investigations on the structure of the europium–lead–tellurate glasses

Abstract

Glasses in the xEu 2O 3·(100-x)[4TeO 2·PbO 2] system where 0 ≤ x ≤ 50 mol% have been prepared using the melt quenching method. The influence of europium ions on the structure of lead–tellurate glasses has been investigated using density measurements, FTIR and UV–VIS spectroscopy. Structural changes produced by increasing the rare earth concentration were followed. The europium and lead ions show a preference towards [TeO 3] structural units causing a deformation of the Te O Te linkages. Structural changes inferred by analyzing the band shapes of IR spectra revealed that the increase of the Eu + 3 content causes the intercalation of [EuO n] entities in the [TeO 4] chain network. The excess of oxygen can be supported into the glass network by the formation of [PbO n] and [EuO n] structural units. The UV–VIS spectroscopy data show that europium ions enter the glass matrix in the Eu 2+ and Eu 3+ valence states, the last being predominant in the studied glasses. The Pb + 2 ions produce strong absorption in the ultraviolet domain.