INFRARED REFLECTANCE SPECTRAL CHARACTERIZATION OF VARIOUS ORGANIC COATINGS ON GLASSES

Oleic acid, polymethyl methacrylate, and polyacrylic acid were coated on soda-lime-silicate and silica glasses from ethyl alcohol, benzene, or water. The structural interaction of each organic compound with the surfaces of the glasses is determined on the basis of varying coating conditions such as solvent, composition of the glass, the coating (ad sorption) time and the aging time in air. Metal chelates are identifie d in the organic coatings on the soda-lime-silicate (SLS) glasses. For oleic acid coatings on the soda-lime-silicate glass developed from be nzene, sodium oleate is the dominant species, while for coatings from ethyl alcohol, the formation of calcium oleate increases. Aging the co ating in air produces additional sodium oleate. Increasing coating tim e increases the formation of calcium oleate. Addition of Al2O3 into th e glass or coating TiO2 onto the glass alters the interaction mechanis ms for oleic acid, and improves the durability of the coating. Polymet hyl methacrylate produces less metal-chelate bonds on the SLS glass su rface than oleic acid due to the presence of a CH3 group in the COOCH3 unit. Coated polyacrylic acid possesses different configurations with different pHs of the preparation solution. Thus, the surface structur al interaction of the organics is closely related to the metal ions on the glass surface possessing high mobility as well as the bonding str ength of the organics with adsorption sites on the glass surfaces. (C) 1997 Elsevier Science B.V.