For the study of quenching medium a special sample is developed that provides high reproducibility of thermal processes occurring on the surface of the cooled product. The results of the cooling method of aqueous solutions with different polymer content are given. The application of thermogravimetric analysis for the study of physical and chemical processes occurring during heating of a synthetic quenching medium is considered. The temperature intervals of endo-exothermic reactions as a result of oxidation of the polymer component of the solution are shown. The reasons for the formation of two extrema on the cooling capacity curve of aqueous polymer solutions are indicated.