Ultraviolet Radiation as a Timing Technique for Outdoor Weathering of Materials

An approach to timing outdoor exposures as well as indoor artificial laboratory exposures based on ultraviolet (UV) radiation measurements has been developed and shows considerable promise for improving correlations between real-time and real-time-to-accelerated weathering programs. The concept of timing exposures on the basis of UV irradiance is the result of sky model studies using precision measurements of the ultraviolet region (300-400 nm) of the solar spectrum. The development of both qualitative and quantitative data bases for the fundamental variables that initiate and drive degradation processes (such as ultraviolet radiation) offers new potential for building a unified approach for evaluating the cause and effect relationships associated with the outdoor weathering of materials.