an arrhenius plot of the time to brittleness at each of the optar temperatures extrapolation of the data line to lower air temperatures predicts the known outdoor aging time of the polypropylene at ambient conditions a correlation coefficient of 0 97 indicates the very high accuracy of the method the optar device of the invention has also been used to test under accelerated aging conditions other polymers such as ethylene vinyl acetate eva polyurethane polyvinylbenzimidazole and ethyl methacrylate ema the optar device and method of the invention generates aging date in the shortest times yet observed in the case of the eva materials induction to change of tensile and modulus occurred at about 6 000 hours for ema induction occurred at about 5 000 hours for polyurethane induction occurred at about 1 000 hours the aging method of the invention eliminate the difficulties associated with irregular spectrum of artificial light sources exposes the specimen to other environmental conditions such as rain and pollution and additionally incorporates a dark cycle many chemical reactions occur during the dark cycle which effect physical properties the only acceleration is from the elevated temperature all other environmental conditions being present in their natural occurrence and intensity in summary the optar device is considered to have the following.