Thin films of various polymers were exposed at ambient temperature to ground-state oxygen atoms (O( 3P)) downstream from a radio-frequency O 2 plasma or glow discharge. The polymer films examined were a polyimide (Kapton), poly(ethylene terephthalate), polystyrene, high- and low-density polyethylenes, poly(vinyl fluoride), poly(vinylidene fluoride), alternating tetrafluoroethylene-ethylene copolymer, polytetrafluoroethylene, and tetrafluoroethylene-hexafluoropropylene copolymer. The relative etch rates for the various polymer films exposed ‘out of the glow’ to O atoms with 0·04 eV translational energy are compared with corresponding literature values obtained from low-pressure, oxygen discharge studies involving exposure ‘in the glow’ and from the Space Shuttle STS-8 flight (with O atoms in low Earth orbit having collisional energy of ≈ 5 eV). The etch rate for Kapton exposed ‘out of the glow’ to 0·04-eV O atoms is also compared with etch rates obtained from various neutral and ion beam experiments (with O O + having impact energies ranging from 0·14 to 800 eV). The etch rate data for Kapton fit reasonably well a logarithmic plot, with positive slope, of reaction probability versus O( 3P) impact energy. ESCA spectra of Kapton before and after reaction with O( 3P) indicated steady-state competition between surface recession (etching) and oxidation.