Optical properties of glass coatings containing Fe and Co

Abstract Glass films of SiO 2 M x O y (M = Fe, Co, FeCo) have been prepared on soda-lime-silica flat glass by sol-gel employing the dip-coating technique. Different parameters affecting solution preparation and application and coating processing (H 2 O/TEOS and R-OH/TEOS ratios, type of catalyst, time and temperature of thermal treatment) were studied, determining the limits in the R-OH, H 2 O, TEOS diagram within which good coatings can be produced. Film thickness varies from 0.2 to 0.9 μm and its dependence on viscosity and oxide concentration in the solution and on the withdrawal rate has been studied. Furthermore, it has been determined the relation between film thickness and microcracks appearance using ROM. Optical properties of coatings have been investigated by spectrophotometric techniques, optical parameters obtained being compared with the corresponding parameters of soda-lime-silica glasses containing the same oxides. From these measurements, the coloration mechanism in each case has been determined.