Degradation of solar glass mirrors paints at marine outdoor site

The behaviour of paint coatings used in commercial glass mirrors was studied under marine environment in Morocco for a period of 3 years. The degradation of each paint system was monitored by following the variation of their color parameters during aging. The obtained results indicated a change in paint color from white to yellow for all tested samples. This color variation is an indicator of a physicochemical degradation of paints. The effect of environmental conditions of the exposure site was also examined by analyzing the influence of each climatic parameter on paint color parameters especially yellowing. This parameter was found to be correlated with the UV dose received by paint samples during aging test. FTIR-ATR analyses conducted on aged paint samples have shown a modification in the intensity of many bonds of infrared spectra. This variation is due to UV degradation of the organic binder and modification in chemical composition of pigments used in these types of paint coatings. XRD analyses have also indicated a variation in pigments concentration of aged paints. Microscopic images taken on paints surface after aging have demonstrated the appearance of crakes on paint layers as well as an increase in white paint thickness. It was also observed that paint coating of aged samples show surface roughness.