UV Radiation UV radiation from sunlight will degrade plastics over time. Polymer photodegradation occurs when non-visible UV radiation made up of short wavelengths breaks down the polymer chains in plastics. This is called the photo-degradation process and results in the deterioration of physical properties.  These include loss of impact strength, changes in color, cracking, loss of elongation and tensile strength as well as chalking of the surface. For example, photodegradation