Glass Surface Atomic Structure after Technological Treatments

Ultrasoft X-ray reflectometry was used to estimate the effects of surface technological treatments (mechanical and chemical polishing, laser annealing) on the atomic short-range order coordination of silicon atoms in the near-surface region of SiO 2-based glass. The fine structure of reflection spectra in the vicinity of the Si L 2,3 ionization threshold for the different angles of incidence was measured. Analysis of the experimental data shows that polishing (both mechanical and chemical) leads to the appearance of a thin surface layer (thickness about 17 nm) characterized by α-quartz-like SiO 4 tetrahedron distortions. The degree of distortion depends on treatment and is largest after chemical polishing and lowest (but noticeable) after laser annealing.