The miscibility between a hydrolyzed silane coupling agent, which had chemically nonreactive organofunctional groups such as propyl groups, and a film-forming polymer [poly(vinyl acetate) PVAc] and its effect on silanol condensation were studied. A mixture consisting of a silane hydrolyzate and PVAc obtained from an alcoholic aqueous solution was investigated with Fourier transform infrared spectroscopy and size exclusion chromatography. Hydrogen bonding between the SiOH groups of the silane and the C=O groups of PVAc and silanol condensation affected by PVAc were examined. The hydrogen bonding and condensation reaction were influenced by the miscibility between the organofunctional group of the silane and PVAc. The miscibility of each system was estimated from the calculated Hildebrand solubility parameter of the organofunctional group. A correlation between the miscibility and the integrated absorbance of the hydrogen-bonded C=O, obtained by least-squares curve fitting, was established. On the basis of the molecular weight of the silane and the number of hydrogen-bonded C=O groups, a micellelike phase was proposed.