Novel oligoperoxides, products of polycondensation of primary alkyl dibromide with tertiary dihydroperoxides, were obtained. The structure of the oligoperoxides was determined by gel permeation chromatography and nuclear magnetic resonance analyses. Their thermal properties were examined by differential scanning calorimetry, and a mechanism of the thermal decomposition was proposed basing on the gel chromatography-mass spectroscopy analysis of the degradation products. (C) 2003 Wiley Periodicals, Inc.