The invention relates to a composition for producing transparent polythiourethane bodies, containing or consisting of A) a polyisocyanate component that contains at least one polyisocyanate having an isocyanate group functionality of at least 2 per molecule, B) a thiol component that contains at least one polythiol having a thiol group functionality of at least 2 per molecule, and if appropriate, C) auxiliary and additional agents, the ratio of isocyanate groups to groups that are reactive to isocyanates being between 0.5:1 to 2.0:1, and said composition being characterised in that it also contains D) at least one aromatic nitrile. The invention also relates to a method for producing transparent polythiourethane bodies by reacting such a composition, to the polythiourethane bodies produced in this manner, to the use of aromatic nitriles for producing transparent polythiourethane bodies, and to a mixture of a polyisocyanate and an aromatic nitrile.

The present invention is directed to an organic polymerizable composition for producing a molded polymeric article. The composition includes a mold release agent of ionic fluoride and/or ionic fluoride precursor present in an amount sufficient to effect at least partial demolding of the polymeric article from a mold. Molded articles also are provided.