M. Elisa, C. Vasiliu, C. Grigorescu, B. A. Sava, A. Diaconu, H. J. Trodahl, M. Dalley, Optical transmission and Raman spectroscopy of aluminophosphate glasses containing chromium and manganese ions, Glass Technol: Eur. J. Glass Sci. Technol. A, 48/5 (2007) 247-251

Title: Optical transmission and Raman spectroscopy of aluminophosphate glasses containing chromium and manganese ions

Abstract: Spectroscopy results of aluminophosphate glasses doped with transition metal (TM) ions (Cr and/or Mn) are reported. Li2O-BaO-Al2O3-La2O3-P2O5 (CrO3, MnO2), Li2O-BaO-Al2O3-La2O3-P2O5 (CrO3-MnO2) and Li2O-Na2O-BaOAl2O3-La2O3-P2O5 (CrO3-MnO2) glasses have been prepared. Ultraviolet-vis, Raman and photoluminescence spectroscopies have been used to investigate the structural and optical properties of the doped glasses. Optical transmission in the ultraviolet-vis range was used to study the oxidation states of the TM ions and the redox equilibria of the transition ion pairs in the aluminophosphate glasses as well as their coordination with oxygen ion ligands (O2-). Aluminophosphate glasses doped with Mn-Cr ions show absorption peaks at 650 and 680 nm, which are characteristic of Ct(3+) ions. The absorption peak at about 450 nm reveals the presence of both Cr3+ and Mn 21 ions. Raman peaks at about 700 and 1200 cm(-1), obtained by 325 and 514.5 nm laser excitation, were assigned to the P-O-P symmetrical stretching mode and to the PO2 symmetrical stretching mode, respectively. The fluorescence peak obtained by 514.5 nm laser excitation is localised at about 600 nm for Mn-doped samples and is due to Mn 21 ions in octahedral coordination. Glass samples containing Cr and Cr-Mn ion pairs exhibit fluorescence emission at about 800 nm due to Cr3+ ions in octahedral and tetrahedral symmetry, no Mn fluorescence was seen in these glasses. The effect of the mixed alkali ions on the spectra of these glass doped with transition ion pairs was also investigated. An increase in the sodium/lithium content results in a nonlinear shift of the ultraviolet transmission edge and improves the fluorescence intensity of the Cr-Mn-doped glass samples.

Key words: Phosphate-Glasses; Luminescence; States