Conditions are presented for application of the Piloyan method to the DTA of poly-nitro aromatic compounds. Activation energies (E) of the thermal decomposition and the initial values TD of the exotherms are determined for trinitrotoluene, trinitro-m-xylene, trinitromesitylene, picryl chloride and dichlorotrinitrobenzene. Linear relationships are derived between the terms E · TD- and published kinetic data on these compounds, obtained by an isothermal manometric method. The mechanisms of the primary steps in the thermolyses of these polynitro compounds are discussed. A negative influence on their thermal stability has been confirmed, arising from the contact of the measured compounds with the glass surface. © 1979 Wiley Heyden Ltd., Chichester and Akadémiai Kiadó, Budapest.