OPTICAL PROFILE OF SURFACE-LAYERS ON A FLOAT GLASS DETERMINED BY ELLIPSOMETRY

Window glass is principally produced by the float technique that causes the diffusion of tin into glass, creating a layer on each face. These have a refractive index (N(F)) that is slightly different from that found in the bulk of the glass (N(S)) and asymptotically approach this value. The Maxwell theory allows one to calculate the reflectance of the system (layer plus glass substrate) considering only the first order in the perturbation deltaN (N(F) = N(S) + delta(N)). The depth profile of the complex refractive index of each layer may be determined with the assistance of multiangle ellipsometric measurements and the reflectance expression.