Dynamics of proton transfer in the sol-gel-derived P2O5-SiO2 glasses

Water diffusion and its role on the proton conduction are discussed in the sol-gel-derived porous P2O5-SiO2 glasses. The diffusion coefficient of wate r in the glass is similar to 10(-7) cm(2)/s at room temperature. The electr ical conductivity is proportional to the logarithm of the number of water m olecules with three separate lines in response to the water concentration. The activation energy determined from the spin-lattice relaxation of proton is, similar to 10 kJ/mol, independent of the water concentration, whereas the activation energy for proton conduction decreases to similar to 10 kJ/m ol with increasing water concentration.