Materials deployed on long-duration space missions such as the Hubble Space Telescope (HST) and the proposed International Space Station (ISS) are subject to high ultraviolet (UV) radiation fluences. Some UV radiation present in space has photon energy high enough to dissociate organic polymer molecular bonds. Induced chemical structure modifications can cause changes in optical, structural, and thermal properties. The present work investigates UV radiation effects on DuPont Kapton(R) H polyimide, polyarylene ether benzimidazole (PAEBI), and DuPont Teflon(R) fluorinated ethylene-propylene (FEP). UV irradiated polymers were characterized with in situ and ex situ spectroscopic ellipsometry (SE). Ellipsometric data acquired on UV modified polymers were best modeled as an exponentially graded layer, as opposed to a single layer or linearly graded layer model. Because photon intensity decays exponentially as a function of depth into absorbing materials, an exponentially graded model should be the most physically realistic. Ellipsometric data provided information about changes in UV absorption spectra, depth of damage, and growth trends in the damaged layer.