AbstractTemperature dependent characteristics of blends of suspension poly(vinyl chloride) with low and high molecular weight plasticizers in the region of processing temperatures have been investigated. The interaction process has been studied under dynamic conditions using the differential thermal analysis (DTA) method under non‐iso‐thermal conditions. As a result of the DTA curves evaluation as well as of the discussion of results it has been shown that the energy transformation occurring during the PVC‐plasticizer system processing is manifested by changes of thermal behavior. The values of heat released, corresponding to the maximum heat transfer rate have been identified as primary data which can be used in correlations describing the quality of plasticizers present in the system. The correlational relations covering the region of processing temperatures provide a “homogeneity” criterion of the system, corresponding to the plasticizing capability of the plasticizer