X-ray photoelectron spectroscopy of sodium aluminosilicate glasses

X-ray photoelectron spectra of Na₂O-Al₂O₃-SiO₂ glasses were measured by a monochromatised Al-Kα XPS instrument with a novel charge control method. Chemical shifts of core level photoelectron spectra of the glass constituent ions were investigated with glass composition with respect to the external energy reference of Au 4f_7/2. Peaks at higher and lower energy sides of the O1s signal were observed and they were ascribed to bridging oxide (BO) and nonbridging oxide (NBO) components, respectively. The BO component was successfully separated into two parts: Si-O-Si (BO(1)) and Al-O-Si (BO(2)). The compositional change for the relative amount of the three Ols components follows an equation derived from an assumption that all aluminium ions were four-coordinated. The Nals signal could not be separated into two components of Na⁺ ions associated with [AlO_4/2]^- tetrahedra and NBOs. However, the Nals chemical shift reflected the change in the bonding characteristics of Na⁺ ions in the glasses.