Abstract: The invention relates to antireflective coatings and to a process for depositing the antireflective coatings on solar collector cover plates, optical elements such as lenses and windows in high-energy visible and near-IR lenses and on other glass or metal or metal-alloy or single crystal surfaces, including the steps of hydrolyzing an alkoxysilane, titanium alkoxide, aluminum alkoxide, tantalum alkoxide, niobium alkoxide, or other alkoxy compounds, or a mixture thereof, depending upon the final coating composition desired; to prepare polymeric solutions of the alkoxy compound/or compounds in which the polymer molecules or macromolecules (i.e. the primary particles) grow with time; depositing layers of coatings from the polymeric solutions by state of the art processes (such as spraying, dipping or spinning method), and drying to form chemically bound microporous gel layers; thermally treating the gel-coating in a manner adapted to remove solvent, excess water and residual organics from the gel coating.