| abstract |
The aim of the present invention is: photochromic resins having improved photochromic properties; articles, notably ophthalmic articles, which are constituted, wholly or in part only, of such resins; radically polymerisable compositions, which are precursors of said resins; and a method of preparing said resins. Said resins are obtained by radical copolymerisation of particular comonomers. They contain an effective amount of at least one acidic additive or of at least one basic additive. They have improved kinetics of return to the light state. |