The invention relates to an article comprising a substrate having at least one major surface coated with a layer A of a material obtained by ion beam assisted vacuum deposition of at least one titanium oxide and of at least one organosilicate compound B, said material having a refractive index at 550 nm higher than or equal to 1.8, an extinction coefficient k at 550 nm lower than or equal to 0.02, and an H:E ratio higher than or equal to 0.046, where H and E designate the hardness of the material and the elastic coefficient of the material, respectively.