PURPOSE: To prevent glass or a mirror from being clouded by a temp. change over a long term, by directly coating the glass or mirror with a resin having hydroxyl groups and by baking and solidifying the resin to form a transparent film.

CONSTITUTION: The surface of plate glass or a morror is degreased with a detergent or the like, coated with a soln., and air-dried until the coated surface is smoothened. The soln. is prepared by diluting polyvinyl alcohol to 1W10% concn., dissolving it perfectly, mixing 1W3C lower alcohol by 10W30% so as to accelerate evaporation, and blending a small amount of a curing agent after dissolving the alcohol perfectly. The coated surface is then dried with hot air at 100W160°C, and the resulting film is solidified by cross-linking under heating to form a transparent thin film producing an anti-clouding effect on the surface of the glass or mirror without causing distortion. Since the film has hydroxyl groups, it has a great affinity for water and produces a remarkable anti-clouding effect. THe resin surface is cured by baking, so the effect can be sustained over a long term.