1. A process for preparing an antireflective coating on a solid substrate comprising: (a) applying to a surface of said substrate a coating composition comprising the composition obtaines by mixing (1) the acid catalyzed hydrolysis and condensation products of a water-silane monomer mixture, and (2) a film-forming amount of an organic polymer having functional groups selected from the group consisting of amino, hydroxy and carboxy, hydroxy and amino, amino and carboxy, and amino, hydroxy and carboxy, said polymer being compatible with said silane monomer and the acid catalyzed hydrolysis and condensation products of said silane monomer, said coating composition being substantially free of preformed metal oxide sol and water-soluble metal salt; (b) curing the applied coating composition; and (c) treating said cured coating with an aqueous inorganic electrolyte solution for a time sufficient to produce a coating having a graded porosity.