Characterization of glass surfaces by X-ray reflectivity

Abstract

Surfaces of soda-lime and borosilicate glasses produced by the float technique as well as polished BK-7, fused silica and aluminosilicate glasses are investigated by means of grazing incidence X-ray reflectometry Thin layers are found at all surfaces with properties which differ significantly from the bulk properties of the respective material. Fused silica surfaces exhibit a hydrated layer with a thickness of approximately 17 nm and a slightly reduced density A thin leached layer with a density of approximately 2 g*cm⁻³ is analyzed on BK 7 glass. A variadon in the rms roughness between 0.7 and 1.5 nm is found for aluminosilicate glasses depending on the polishing procedure. Pronounced differences are obtained between the air and the tin bath side of soda-lime float glass, whereas for borosilicate float glass only small differences in density between the two sides of the glass are measurable. The evolution of the initial stages of corrosion is demonstrated on soda-lime glass in dependence on the storage time.