Porous glasses (PGs) with 4 nm in diameter pores were prepared utilizing a spinodal-type phase separation of Na2O–B2O3–SiO2 glass, and their surface was modified using titanium tetraisopropoxide. Fourier transform infrared measurements revealed that the absorbance for strong hydrogen-bonding OH groups increased after the modification. Bond overlap population (BOP), which is directly related to the strength of the covalent bond, between O and H of OH groups were calculated using density functional theory and first-principles calculations. BOPs decreased by the introduction of Ti atoms on pores. The proton conductivity at 80°C and 90% relative humidity of the titania-modified PG was about five times higher than that of unmodified PG.