FLUORESCENT ENTITY, DYEING COMPOSITION CONTAINING AT LEAST ONE FLUORESCENT ENTITY COMPRISING AT LEAST ONE HETEROCYCLE, WITH AT LEAST ONE INTERNAL CATIONIC CHARGE, AND METHOD FOR LIGHTENING KERATIN MATERIALS USING SAID AT LEAST ONE FLUORESCENT ENTITY
The invention relates to a dyeing composition containing a thiol/disulphide fluorescent colorant comprising a heterocycle, and to a method for colouring keratin materials, especially keratin fibres, particularly human keratin fibres such as hair, with a lightening effect, using said composition. The invention also relates to novel thiol/disulphide fluorescent colorants and the uses thereof for lightening keratin materials. Said composition produces a lightening effect which is especially tenacious and visible on dark keratin fibres.