UV degradation on polymer chains?

Question

I need help understanding the process of UV degradation & photo oxidation on an organic polymer (both alkyd & acrylic paint films more specifically). Just how does UV light lead to bond scission and cleavage on benzene rings and or its substituents?

Answer 1

UV rays have very high energy and their energy levels are close or higher than the bond energies of organic molecules. Thus interference of the molecular orbitals with UV light leads to a breakdown.