Optical properties of soda-lime glass manufactured by the float process were investigated using spectroscopic ellipsometry and intensity transmission measurements. Thickness and optical properties of surface layers on the air and tin sides were determined with ellipsometry. The tin side surface layer shows a graded refractive index with a non-linear profile. Intensity transmission data were used to quantify absorption in the bulk glass. Transmission-mode generalized ellipsometry characterized residual birefringence in the bulk glass. Birefringence effects on ellipsometric delta data were corrected using a simple empirical offset with 1/wavelength dependence. A general optical model for soda-lime glass is presented which can be used for subsequent analysis of coated soda-lime glass and other transparent substrates. (C) 2010 Elsevier B.V. All rights reserved.