Effect of P2O5 addition on the structural and spectroscopic properties of sodium aluminosilicate glass

The structural and spectroscopic properties of Na2O-Al2O3-SiO2-xP(2)O(5) glasses (x = 0 to 7 mol%) are investigated. Both Raman and IR spectra reveal that discrete phosphate species ([PO4](-3), [PO3O1/2](-2)) with low polymerization degree can be formed in the silicate glass. These phosphate structures scavenge non-bridging oxygen ions and cations from the silicate network, resulting in an increase of the glass transition temperature. According to the Judd-Ofelt intensity parameters (Omega(2), Omega(4), Omega(6)) of Er3+, the asymmetry of local environment around Er3+ becomes higher, and the bond covalency between Er3+ and O2- decreases after P2O5 is introduced. In the emission spectra, photoluminescence intensity increases with increasing P2O5 concentration and the spectra are inhomogeneously broadened, revealing that the ligand electric field around Er3+ is dramatically changed, and the glass matrix becomes disordered.