Glow discharge polymer (GDP) is selected as ablation layer for inertial confinement fusion experiments. However, simulations suggested that the surface oxygen of the GDP shells is the primary cause for the growth of hydrodynamic instability in implosions. The GDP films were stored under various atmospheric and light conditions, and their chemical bond structure and oxygen content were characterized. The results have shown that the oxidation of the GDP films is caused by rapid photooxidation and slow spontaneous oxidation. As a dominant oxidation pathway, the photooxidation resulted from the absorption of photon energy by the GDP films to generate free radicals, which then reacted with oxygen to form alcohols, aldehydes, ketones, esters and carboxylic acids. Both the photooxidation and spontaneous oxidation of the GDP films exhibited unsaturated oxidation. The oxidation process firstly occurs on the surface and gradually diffuses into the interior of the GDP films.