The addition of heat stabilizers is essential for preventing the degradation of poly(vinyl chloride) (PVC) during its processing. The heat stabilizers consumed in the first run have to be made up before the reprocessing of recycled PVC. In this study, solvent-cast films, which were prepared from granulated postconsumer PVC bottles mixed with plasticizers and thermal stabilizers, were used. The films were subjected to various heat treatments. No considerable structural change upon heat treatments at 140-160degreesC was found in IR and differential scanning calorimetry analyses. Polyene formation observed through ultraviolet analysis was not severe, indicating that the added stabilizers worked well in preventing degradation. The weight loss during the heat treatments was attributed partly to the decomposition of PVC and the evaporation of volatile components and mainly to the removal of the solvent upon heating. Although this study was conducted with water bottles that were to be recycled, it may be equally well applied to other similarly formulated PVC-based materials, such as packaging films. (C) 2003 Wiley Periodicals, Inc.