Method for dyeing a plastic substrate of high refractive index and substrate obtained by this method

Method for dyeing a substrate prepared by curing a polymerizable composition comprising at least one monomer containing at least one episulfide group and optionally at least one thiol group, said method comprising the following successive steps:

• providing a dye solution comprising at least one dye, or dye precursor, and at least one carrier in at least one solvent, the carrier being chosen from the compounds represented by the following formulae (1) and (2):
• wherein R1, R2, R3 and R4 are each selected from the group consisting of the following radicals:
• alkyl having from 1 to 10 carbon atom, H, —CH2SH, —CH2SCH2CH2SH,
• provided that R1, R2, R3 and R4 are not H or an alkyl simultaneously, or that if any three of R1, R2, R3 and R4 are H or an alkyl, the other radical consists of one of the following radicals:
• wherein m denotes an integer from 1 to 3;
• And
• at least partially immersing the substrate in the dye solution for a time sufficient to allow the effective tinting of the substrate.