The tetrafunctional epoxy resins were prepared starting from diaminodiphenylmethane, diaminodiphenylether, and diaminobibenzyl. The obtained resins were characterized by IR and H-1-NMR spectroscopy, rheological and thermal techniques. The polymerization reaction was investigated by viscosimetry. The flow activation energy and the polymerization activation energy were evaluated from the rheological data and from the critical parameters (critical time and critical viscosity at gel point). The viscosity measurements and gel time determination showed slight differences between the synthesized resins,