Neat polyimide matrix (PMR-15) film samples were prepared by two methods: press-forming and autoclave-forming. For each method, three different cure cycles, denoted by the highest temperatures during cure (288 degree C, 306 degree C and 329 degree C), were investigated. The curing mechanism was investigated with thermoanalytical techniques (pressure differential scanning calorimetry and thermogravimetric analysis). Possible structural differences in the samples were correlated to the processing variables and related to the results from dynamic mechanical analysis (DMA). The DMA results showed that the films produced by the three cure cycles either in the press or in the autoclave were quite identical. For the three cure cycles investigated, it was observed that post-curing had the strongest effect on the low temperature cured samples (288 degree C and 306 degree C cured samples); while the cure temperature was proportionally related to the resulting sample Tg and stress-free temperature.