Thermal analysis of semicrystalline poly(vinyl alcohol) reveals the existence of up to three energetically distinct states of water within the polymer structure. Wide angle X-ray studies indicate that diffusion of water into semicrystalline samples of the polymer gradually destroys the crystalline regions of the polymer, although water is found to not inhabit intact crystallites. The nonfreezing water is responsible for the destruction of crystalline regions by a mechanism of disruption of intermolecular hydrogen bonds in the interface region between the crystalline and swollen amorphous regions. Water does not inhabit the polymer in clusters as freezable water until most of the inter and intra molecular hydrogen bonding has been disrupted by the nonfreezing water.