A water-repellent glass comprising a uniform and optically transparent
silica film with excellent durability and hardness is prepared by a
process which comprises: (a) preparing a colloidal silica suspension by
hydrolyzing and polycondensing an alkoxysilane in an organic solvent under
a basic condition in the presence of water, and then treating the
colloidal silica suspension under an acidic condition, to obtain a silica
dispersion containing cross-linked spherical silica particles and linear
polysiloxane, (b) combining the silica dispersion with a mixed solvent
composed of acetic acid and an alcohol to obtain a coating composition,
(c) applying the coating composition on the surface of a glass substrate
to form a silica layer therefrom, (d) heat treating the silica layer to
provide a silica film on the glass substrate, and (e) applying a
water-repellent agent on the silica film to provide the water-repellent
glass.