The absorptions of light by bilirubin also results in the generation of excited-state bilirubin molecules that react with oxygen to produce colorless oxidation products, or photooxidation products. This process occurs more slowly than configurational or structural isomerization. Photooxidation products are primarily excreted in the urine. The image below provides a schematic of the conversion of normal bilirubin to configurational isomers, structural isomers, and photooxidation products and the respective routes of excretion from the body.