THE EFFECTS OF ULTRAVIOLET RADIATION ON POLYCARBONATE GLAZING Effects of UV on polycarbonate glazing G.F. TJANDRAATMADJA and L.S BURN CSIRO Building, Construction and Engineering, Melbourne, Australia

Unstabilised bisphenol A polycarbonate samples were aged under UV radiation for periods of up to 3000 hours. The samples were then characterised using FTIR/ATR, GPC, SEM, microscopy, light transmission and colour changes. The changes in optical properties were related back to the changes in the polymer microstructure and composition. In this study, the molecular weight of polycarbonate was seen to decrease during UV exposure, making it susceptible to embrittlement and surface erosion. This coupled with the discoloration of the polymer contributed to the loss of optical properties, including reduced light transmission, loss of gloss, increased haze, and discoloration. In the case of reduced light transmission and yellowing of polycarbonate, the degradation mechanisms were identified through infra-red spectroscopy. Photo-induced yellowing was accelerated by humidity, while the reduction in other optical properties was more severe in low humidity environments.