In order to elucidate the structure of poly(vinyl alcohol) (PVA) gels, the gels studied were aged for as long as 500 days at 30-degrees-C. The original gel was formed from PVA solutions in a mixed solvent of dimethylsulfoxide (DMSO) and water by chilling at -34-degrees-C for one day. The aged gel was shown to have a well grown crystal phase, in that the melting endotherm from differential scanning calorimetry could be clearly separated into two or three components, which were named A, B and C, in order of melting temperature. The enhancement of the gel modulus and the solvent exclusion observed in the aged DMSO/water gels could be attributed to phase separation, which facilitates crystallization into the B and C components. The A component was shown not to bear a strong relationship to the high modulus and the exclusion of solvent, although it may be the most common crystallite grown from PVA solutions.