Poly(imide-silica) hybrid materials with covalent bonds were prepared by (3-aminopropyl)methyldiethoxysilane (APrMDEOS) terminated amic acid, water, and tetramethoxysilane (TMOS) via a sol-gel technique. Infrared (IR), Si-29 and C-13 CP/ MAS nuclear magnetic resonance (NMR) spectroscopy, and thermogravimetric analysis (TGA) were used to study hybrids containing various proportions of TMOS and hydrolysis ratios. The microstructure and chain mobility of hybrids were investigated by proton spin-spin relaxation T-2 measurements. The apparent activation energy E-a for degradation of hybrids in air was studied by the van Krevelen method.