A new class of proton-conducting polymer was developed via the sol-gel process from amino-containing organic-inorganic hybrids by the treatment of poly (allylamine) with 3-glycidoxypropyltrimethoxysilane doped with ortho-phosphoric acid. The polymer matrix contains many hydropbilic sites and consists of a double-crosslinked framework of polysiloxane and amine/epoxide. Differential scanning calorimetry results suggest that hydrogen bonding or electrostatic forces are present between H3PO4 and the amine nitrogen, resulting in an increase in the glass-transition temperature of the poly(allylamine) chain with an increasing P/N ratio. The (31)p magic-angle spinning NMR spectra indicate that three types of phosphate species are involved in the proton conduction, and the motional freedom of H3PO4 is increased with increasing P/N ratios. The conductivity above 80 degrees C does not drop off but increases instead. Under a dry atmosphere, a high conductivity of 10(-3) S/cm at temperatures up to 130 degrees C has been achieved. The maximum activation energy obtained at PIN = 0.5 suggests that a transition of proton-conducting behavior exits between Grotthus- and vehicle-type mechanisms. The dependence of conductivity on relative humidity (RH) above 50% is smaller for H3PO4-doped membranes compared with H3PO4-free ones. These hybrid polymers have characteristics of low water content (23 wt %) and high conductivity (10(-2) S/cm at 95% RH), making them promising candidates as electrolytes for fuel cells. (c) 2005 Wiley Periodicals, Inc.