Definition - What does Ultraviolet Resistance mean?
Ultraviolet resistance is the ability of a material, often a polymer, to withstand the degradation that can be caused by exposure to ultraviolet light. If a polymer has low ultraviolet resistance, it could be subject to premature or unintended failure as a result of deterioration.
Corrosionpedia explains Ultraviolet Resistance
Polymer selection is important when dealing with an environment with high levels of ultraviolet radiation. Some polymers have a lower ultraviolet resistance than others. For example, polypropylene is a polymer that has very low ultraviolet resistance. In an application with high amounts of ultraviolet light, it will deteriorate more rapidly than some other polymers. Polytetrafluoroethylene (PTFE), on the other hand, is designed to have higher ultraviolet resistance, so it is more suitable for outdoor applications than polypropylene.
Ultraviolet resistance can be increased by adding certain elements and chemical compounds when the polymer is being formed. If the ultraviolet resistance of a polymer is low, other means such as a coating or other forms of shielding can be used to preserve the polymer.