Photodegradation is the breakdown of a polymer due to exposure to light, particularly ultraviolet (UV) light. UV light can cause chain scission and other chemical changes in the polymer, leading to a deterioration of its properties. Photodegradation is a concern for polymers used in outdoor applications or exposed to sunlight.

光降解是由于暴露于光（尤其是紫外线 (UV) 光）导致的聚合物分解。紫外线会导致聚合物断链和其他化学变化，导致其性能下降。对于用于户外应用或暴露在阳光下的聚合物来说，光降解是一个问题。