Etude Ellipsométrique du Mécanisme Fondamental de Polissage du Verre

Polish layers in the mechanically polished surfaces of some optical glasses, Pyrex, Vycor and silica glass are studied ellipsometrically, and the polishing mechanism is discussed. The increase in refractive index of the polish layer of silica glass has been attributed to the surface densification of glass by polishing particles [H. Yokota et al.: Surface Sci. 16 (1969) 265]. Based on this assumption, it is inferred from the data showing an increase in refractive index from previous papers on silica glass that a local pressure of the order of 150–300 kg/mm2 is acting through a microscopic contact region between the polishing particle and the glass surface. Discussions lead to a conclusion that surface plastic flow is hardly possible to occur under ordinary polishing pressures. It is expected that the local polishing pressure can be transmitted instantaneously through polishing particles to the glass surface, because of the rheological character of pitch polisher.