Solar UV, heat and water act synergistically on polymers and induce ageing processes. In the first step, a photon is absobed and excites a molecule into a higher eneryg level. From this excited state, photo degradation starts and is often propagated into a cascade of chemical reactions, which are all accelerated by increased temperture.
Basic understanding of the primary and secondary photo chemical steps is critical to choose the right accelerated weathering test and to develop effective stabilization packages.
