Ultraviolet laser radiation at 248 nm and 266 nm was used to ablate low density (0.04 to 0.14 g/cm3) microcellular polystyrene and TPX foams at laser fluences between 0.1 and 1000 J/cm2, The dependence of the etch rate on laser fluence and foam density is consistent with a linear absorption mechanism for the initial stages of polystyrene ablation. Studies of the morphology and chemical composition of the ablated foams as a function of laser fluence and foam density show that the degree of melting increases at the higher foam densities. Blackbody and radical specie contributions to optical emission from the ablated foam were readily resolved for correlation with laser fluence, foam density, absorption spectra, and etch depth. Temperatures in excess of 3000 °K are calculated from emission spectra observed during the ablation of polystyrene foams. From this data we conclude that chemical and thermal changes in the ablated foam are influenced by the absorption spectrum as well as the density of the foam.