AbstractThe mass spectra were determined of three epoxy resin precursors:N,N‐bis‐(2,3‐epoxypropyl)‐N′,N′‐dimethyl‐4,4′‐diaminodiphenylenemethane (G2A);N,N′‐bis‐(2,3‐epoxypropyl)‐N,N′‐dimethyl‐4,4′‐diaminodiphenylene methane (G2S); andN′,N′,N′,N′‐tetrakis‐(2,3‐epoxypropyl)‐4,4′‐diaminodiphenylene methane (TGDDM); and of three related model compounds:N,N‐dimethylaniline (DMA);N‐methyl‐N‐glycidylaniline (MGA) andN,N‐digrycidylaniline (DGA). The results helped to confirm the structure of the resin precursors and are intended to pave the way for subsequent thermal degradation studies of cured resin samples. Despite the similarity in chemical structure of the compounds studied th