Process for the production of a photochromic article

摘要

The invention relates to a process for the production of a photochromic article comprising a polymer and containing at least one spirooxazine compound, with the following process steps: - the polymerisable monomer used is an acrylate monomer or a methacrylate monomer or a mixture of a plurality of these monomers, - the photochromic dyes and a polymerisation initiator are mixed into the polymerisable monomer, - the resultant mixture is introduced into a casting mould, polymerised and cured. The invention is distinguished by the fact that - in order to achieve a neutral grey or brown photochromic colouration of the polymerisable mixture, a plurality of photochromic dyes are added, of which at least one is not a spirooxazine, and - the concentration of the spirooxazine compound(s) is not more than 0.045 % by weight, based on the weight of the monomer employed, and - the concentration of the polymerisation initiator(s) is more than 1 % by weight, based on the weight of the monomer employed.