Definition - What does Photodegradation mean?
Photodegradation is the change, typically undesirable, in the properties of a material. Quite literally, it means the degradation of a material due to photon exposure. Photo degradation is a major concern with some polymers and other materials, where ultraviolet (UV) light causes the polymer to oxidize, thus making them brittle.
Corrosionpedia explains Photodegradation
Photodegradation can occur to many different substances, such as chemicals, nutrients and colored dyes, to name a few. Chemicals can be rendered useless over time when exposed to excessive ultraviolet light because the chemical's molecules oxidize and lose their ability to perform their intended function. Colors that are made with organic dyes will fade over time when ultraviolet light is impressed upon them. Nutrients, while they may retain their ability to nourish, may have their taste or smell changed as a result of ultraviolet light causing oxidation.
Photodegradation is a primary concern for some types of polymers in outdoor applications or applications where other sources of ultraviolet light are present. To reduce the amount of degradation that occurs, several prevention methods can be used. One is coating the polymer with a substance that does not photodegrade. Shielding the polymer from the sun or ultraviolet light source is another option. There are also polymers that do not readily photodegrade as fast as others.
Proper consideration should be taken when selecting a polymer for an application where ultraviolet light exposure is expected.