Organic-inorganic hybrids were prepared with a diglycidyl ether of bisphenol A (DGEBA) type epoxy and silane-modified isocyanuric acid triglycidyl ester via the sol-gel process. The DGEBA-type epoxy was modified by, a coupling agent to improve the compatibility of the organic and inorganic phases. The sol-gel technique was used successfully to incorporate silicon and nitrogen into the network of hybrids, increasing the thermal stability. Fourier transform infrared and 29 Si-NMR were used to characterize the structures of the hybrids. The results revealed that trisubstituted siloxane bonds (T-3) was the major environment forming a network structure. The morphology of the ceramer was examined with scanning electron microscopy, Si mapping, and transmission electron microscopy. The particle sizes were less than 100 nm. The hybrids were nanocomposites. The ultraviolet-visible spectra of the epoxy hybrid showed no obvious absorbance over a range of 400-800 nm. This phenomenon revealed that the hybrids were transparent. The thermogravimetric analysis revealed that the char yields of the hybrids increased with the contents of the inorganic components. The integral procedure decomposition temperatures of the hybrids were higher than that of the pure epoxy. The thermal stability of the hybrids increased with the contents of the inorganic components. The inorganic components could improve the thermal stability of the pure epoxy. (c) 2007 Wiley Periodicals, Inc.