Abstract: The present invention relates to an optical article comprising a substrate having at least one main surface coated with a coating comprising at least one layer of an abrasion and/or scratch-resistant coating, wherein the abrasion and/or scratch-resistant coating is formed from a composition comprising at least one epoxy compound bearing at least one silicon atom having at least one hydrolysable group directly linked to the silicon atom and at least one group comprising an epoxy function linked to the silicon atom through a carbon atom, and/or a hydrolysate thereof, at least one plasticizer, a silane hydrolysate and colloidal silica, wherein the total amount of plasticizer in the composition is lower than 10 wt % of the dry extract of the total composition, and wherein the weight ratio of silane of formula (I) to plasticizer is higher than 0.4 in the dry extract of the composition.

Abstract: The present invention pertains to a method for producing a colloidal suspension of zirconia particles, comprising the following successive steps: a) subjecting a mixture of zirconium oxychloride and an alkali metal halide in an aqueous solvent to hydrothermal treatment at a temperature above 150° C., so as to obtain a suspension in the form of a two-phase mixture comprising a slurry and a supernatant, b) without first peptizing it, desalting said suspension so as to form a colloidal suspension of zirconia.

Abstract: The present invention pertains to a method for producing a colloidal suspension of zirconia particles, comprising the following successive steps: a) subjecting a mixture of zirconium oxychloride and an alkali metal halide in an aqueous solvent to hydrothermal treatment at a temperature above 150° C., so as to obtain a suspension in the form of a two-phase mixture comprising a slurry and a supernatant, b) without first peptizing it, desalting said suspension so as to form a colloidal suspension of zirconia.