This study describes a novel experimental method for measuring the permeation of oxygen through thin barriers using the UV light-induced oxidation of a polymer as a sensor. This method is based on the photooxidation of poly(ethylene oxide) (PEO) encapsulated in a bag formed from the barrier. The method was applied to three polymers with different oxygen barrier properties (polymethylmethacrylate (PMMA), polyethyleneterephtalate (PET) and polyvinylalcohol (PVA)), and the results were compared with values reported in the literature. The results confirm that this method yields oxygen permeability coefficients in good agreement with the literature data. In addition, the experimental method is easy to apply.