A liquid composition stable during storage and polymerizable radically into organic glasses having a high refractive index, containing:(A) from 20 to 80% wt of a mixture of monomer and oligomers of a carbonic allyl derivative representable by the formula (I): ##STR1## where: X=halogen (except fluorine);a and be independently assume the values 1 or 2;n assumes values from 1 to 5 on condition that at least 10% by weight of the mixture consists of carbonic allyl oligomer derivatives (n>1); and(B) from 80 to 20% by weight of a liquid monomer copolymerizable with the component (A) and chosen from diallyl isophthalate, diallyl terephthalate, triallyl cyanurate and triallyl isocyanurate.