The object of the present invention is a radically polymerisable composition comprising a mixture of at least: one or more (meth)acrylate difunctional monomer(s) of type (a): of formula (A) and/or of formula (A'); and one or more alkenic difunctional monomers of type (b): of formula (B) and/or of formula (B') and/or of formula (B"). The invention also relates to the resins obtained by polymerization of the compositions and the ophthalmic articles constituted, wholly or in part, of the resins, and the articles may optionally have photochromic properties. ##STR1##