抄録
Glass samples of Na2O–P2O5–SiO2 containing Nd2O3 with ～0.3 mol% were prepared by melting on a hotfilament and quenching. Absorption spectra of 4f-4f forced-electric dipole transitions of Nd3+ were evaluated with a commercial spectrophotometer. Local structures around Nd3+ ions were estimated by the shape, peak wavelengths, and absorbance of 4I9/2→4G5/2, 2G7/2 and 4I9/2→4F5/2, 2H9/2 transitions with the interpretation of previous results concerning EXAFS analysis. Absorption spectra indicate that the composition at which Nd3+ ions are selectively coordinated by PO4 tetrahedra is [Na2O]/[P2O5] 2 in a molar ratio for Na2O–P2O5 glasses and [Na2O]/[P2O5] 1 for Na2O–P2O5–SiO2 glasses. IR spectroscopy results the glasses mainly consist of PO4 Q2 units and P–O–P bonding. Elution tests reveal that Nd constituents, coordinated with PO4 tetrahedra, with a large fraction of ～0.9 were dissolved into ultra-pure water at 30ºC for the phosphosilicate glasses with [Na2O]/[P2O5] 1.
