Structural characterization of the near‐surface region of soda–lime–silica glass by X‐ray photoelectron spectroscopy
Barsheek Roy, Felix Baier, Andreas Rosin, Thorsten Gerdes, Stefan Schafföner
Abstract
Abstract The structural chemistry of the near‐surface region of soda–lime–silica (SLS) glass is described in terms of silicate network connectivity using X‐ray photoelectron spectroscopy (XPS). A thorough investigation of O1s and Si2p spectral lines by sequential XPS measurements, accompanied by Ar + sputtering, revealed the variation of concentration of bridging oxygen, non‐bridging oxygen (NBO), and hydrous species (SiOH/H 2 O) as a function of depth from the glass surface. The O total /Si atomic ratio was calculated to vary in the range of 2.90–3.74 throughout the depth of sputtering for a total duration of 110 min, while considering each of the aforementioned oxygen speciations in the curve‐fitted spectra of O1s orbital. The glass surface up to a depth of 1–3 nm had the highest O total /Si ratio of 3.74, which was representative for a mechanically weak structure with Q 0 and Q 1 species, marked by the respective linkages of four and three NBOs per silica tetrahedral unit. This dictates the vital contribution of the hydrous species associated with silanol groups to the near‐surface structure of SLS glass.