Fast polymerizable/curable episulfide based composition, polymerization/curing process and optical articles resulting therefrom

Polymerizable composition for making episulfide based resins comprising:

• A) at least one episulfide compound bearing at least one episulfide and at least one functional group capable of polymerizing with episulfide groups, and
• B) an effective amount of a polymerization catalyst system comprising:
• at least one salt of formula
• Mmp+Yn−
• wherein
• Mp+ is a cation selected from the group consisting of alkaline metals, alkaline earth metals, transitions metals and ammonium groups of formula NR+4 in which R is an alkyl radical,
• Y− is an anion such as the corresponding acid YH has a pKa fulfilling the condition 0.5≦pKa≦14 with the proviso that when Mp+is an ammonium group, the catalyst system further comprises an electro-donor compound,
• P is the valency of the cation,
• n=m×p, and
• at least one tertiary amine.