Novel aliphatic aminimides were synthesized from the corresponding carboxylic acid esters, 1,1-dimethylhydrazine, and epoxides in 54-95% yields. Bulk polymerization of glycidyl phenyl ether (GPE) with 3 mol % of the aminimides was evaluated by DSC as a model process for curing of epoxy resin. All the aminimides showed no exothermic DSC peak below 120 degrees C but showed sharp exothermic peaks above 137 degrees C, indicating good thermal latency. Good relationships were observed between the calculated bond length from the carbonyl carbon to the ct-carbon of the aliphatic group (R-C), DSC onset temperatures, and the thermal dissociation temperatures (T-d's) of the aminimides. The aminimide with a longer R-C bond length showed lower T-d and DSC onset temperature, that is, higher activity.