A novel method of utilizing quaternary ammonium compounds to accelerate the polymerization of 2-pyrrolidone is disclosed. The method consists of dehydrating the hygroscopic quaternary ammonium compound by adding it to 2-pyrrolidone and distilling over, under vacuum, a portion of the pyrrolidone whereby the water is removed and then adding the residue to a conventional anhydrous polymerization mixture composed of an alkali metal salt of 2-pyrrolidone dissolved in 2-pyrrolidone and effecting polymerization by adding a polymerization initiator and heating the mixture to a temperature ranging from about room temperature to about 60.degree. C.