The combined effect of light, heat and water leads to the aging of polymers. These “weathering” effects initially occur at the molecular level. "Service lifetime" is reached when the degradation has accumulated into a level of changes in the desired properties above the pass-fail criterion.
UV stabilizers extend the polymer service life by protecting against photo degradation and delaying the ageing processes. The effectivity of a given stabilization can be determined by performing laboratory weathering tests.
