Abstract
The evolution of transmittance in UV and gamma irradiated polymers at elevated temperature was extensively investigated. We focus on the evolution of transmittance in UV-irradiated PLA/PMMA blends. The transmission loss caused by UV light was attributed to the generation of color centers. The optical properties of PLA and PMMA are contrary. Therefore, after isothermal annealing, the optical absorbance change is classified into three cases: PLA, PMMA and PLA/PMMA blends. The absorbance at the wavelength of 330 nm was assumed to be proportional to the concentration of color centers. A first-order kinetic model was proposed to analyze the experimental data. The rate constant satisfies the Arrhenius equation, with the activation energy slightly increasing with the increase of UV dose.