Other than water barrier, protection from UV radiation (100 -400 nm wavelength of the electromagnetic spectrum) is a common requirement for packaging materials. UV light is responsible for the degradation of photosensitive species due to its ability to cleave C-C, C-O, and O-H bonds resulting in the formation of radicals. Thus, a complete shielding of light in such wavelength is needed to prolong the shelf-life of products such as drugs and food. As an example, vitamins contained in milk are decomposed by UVlight, limiting the use of neat PET which is partially transparent to such radiation.