Hybrids containing silicon, phosphorous and nitrogen were prepared by the sol-gel method and compared with pure epoxy. The silicon, phosphorous and nitrogen components were successfully incorporated into the networks of polymer. Thermogravimetric analysis (TGA) was used for rapid evaluation of the thermal stability of different materials. The integral procedure decomposition temperature (IPDT) has been correlated the volatile parts of polymeric materials and used for estimating the inherent thermal stability of polymeric materials. The IPDT of pure epoxy was 464 degrees C and the IPDTs of hybrids were higher than that of pure epoxy. The thermal stability of hybrids increased with the contents of inorganic components. The inorganic components can improve the thermal stability of pure epoxy. Two methods have been used to study the degradation of hybrids containing silicon, phosphorous and nitrogen hybrid during thermal analysis. These investigated methods are Kissenger, Ozawa's methods. The activation energies (E-a) were obtained from these methods and compared. It is found that the values of E-a for modified epoxy hybrids are higher than that of pure epoxy. The hybrids of high activation energy possess high thermal stability. (c) 2006 Elsevier B.V. All rights reserved.