To favor the curing process of epoxy resin by cross-linking and not by vitrification, the use of a tertiary amine salt is proposed. The curing reaction between diglycidyl ether of bisphenol A and tris-(dimethylaminomethyl) phenol tri(2-ethyl hexanoate) is studied by differential scanning calorimetry (DSC). Studies are carried out at different concentrations of amine salt: 5, 7.5, and 10 wt%. The vitrification is observed at low concentrations of the amine salt in curing experimental assessments. Furthermore, the experimental characterization of the glass transition temperature at different amine salt concentration allows inferring the polymer network connectivity. Later, the Kissinger method is used to calculate the activation energy. Finally, a reaction mechanism between the epoxy resin and the curing agent is proposed. The reaction mechanism is based on four reactions that may occur. In the most likely reaction happening in the curing, the 2-ethyl hexanoate behaves as a catalyst through three types of esterification. The characterization and mechanism of the curing reaction of the epoxy resin DER 331 and the amine salt tris-(dimethylaminomethyl) phenol tri(2-ethyl hexanoate) have not been reported previously, so it is a novel support of technological relevance for the cure of epoxy community. POLYM. ENG. SCI., 2017.