This invention relates to an N-vinyl heterocyclic copolymer in substantially pure deionized water or in aqueous alcoholic solution which exhibits significantly reduced color and odor and which is obtained by contacting an alcohol-copolymer mixture with water and a nitrogen containing, trivalent boron complex compound selected from the group of borane-ammonia, borane-lower alkylamine, tetra-lower alkyl ammonium octahydrotriborate, morpholine-borane, lower alkyl morpholine-borane, silylamino borane and mixtures thereof and stripping alcohol from the resulting mixture under vacuum at between about 100 and about 740 mm Hg below absolute whereby an aqueous, 10-70 wt. % solids solution of the copolymer is obtained having a water white color stability of more than a year.