The local structure of Sm-doped aluminosilicate glasses prepared by sol–gel method

The local structures of Sm and Al in Sm-doped aluminosilicate glasses prepared by the sol–gel method were investigated by using 27Al MAS NMR spectroscopy and X-ray radial distribution function (RDF) analysis. It is found that at low alumina content (1 mol%), the glass network consists of SiO4 and AlO6 structural units. At higher alumina content, AlO4 and AlO6 structural units coexist in the glasses. It is considered that the formation of AlO4 results in enhancement of the dispersion of Sm ions in these glasses. The average coordination number of Sm in a 10Al2O3 · 90SiO2 · 1Sm2O3 glass slightly increased from 7.1 to 8.5 after heat-treatment in reducing atmosphere. The role of Al ions in dispersing Sm ions in a glass matrix is discussed.