The thermal stability of N-methyl derivatives of 7H-difurasanofuroxanoazepine and 7H-trifurazanoazepine in non-isothermal and isothermal modes has been studied. Formal-kinetic regularities of decomposition and temperature dependences of reaction rate constants have been determined. The thermal stability methyl, propargyl, cyanomethyl, allyl and amine derivatives of azepines is compared.