Factors Affecting Microscopic Basicity of Silicate Glasses from the Perspective of O1<i>s</i> Binding Energy
Masahiro Tsuji, Masahiro Hotta, Takashi Watanabe, Rie Endo, Masahiro Susa, Miyuki Hayashi
Abstract
The factor affecting the microscopic basicity of oxygen in the SiOSi bond are investigated on the basis of the O1 s binding energy measured by X‐ray photoelectron spectroscopy (XPS). The samples used are SiO 2 , Na 2 OSiO 2 , CaOSiO 2 , CaOMgOSiO 2 , and CaOAl 2 O 3 SiO 2 . For analysis on clean surfaces, samples are finally prepared by fracturing in a vacuum in an XPS system. From the O1 s spectra, derived are the centers of gravity of the O1 s spectra and the binding energies of O1 s in the SiOSi, SiOAl, AlOAl, SiONa, SiOCa, and SiOMg bonds. A good linear relationship is found between the center of gravity of the O1 s spectra and the optical basicity, suggesting that the center of gravity of the O1 s spectra is a reasonable basicity index of silicate glasses used in this work. It is also found that there is a linear relationship between the binding energy of O1 s in the SiOSi bond and the optical basicity, irrespective of the glass systems. This indicates that the experimental microscopic basicity of oxygen in SiOSi bond is affected not only by the first neighboring ions of oxygen but also by the composition of the sample.