Organosiloxane compositions

A moisture curable composition capable of cure to an elastomeric body, the composition comprising (a) an organopolysiloxane having not less than two silicon-bonded hydroxyl or hydrolysable groups; (b) a silane of the general formula G2-Si-R12, wherein each group is reactable with the hydroxyl or hydrolysable groups in (a), and each R1 group is an alkyl group having from 1 to 10 carbon atoms, an alkenyl group, an alkynyl group an aryl group or a fluorinated alkyl group; (c) one or more fillers and (d) a photocatalyst. Preferably at least one R1 group is unsaturated, but in the absence of this there is provided an additional component in the form of (e) an unsaturated compound selected from the group of an unsaturated short chain siloxane, an unsaturated cyclic siloxane, an unsaturated fatty acid an unsaturated fatty alcohol or an unsaturated fatty acid ester. The cured product is generally used as a sealant, which avoids dirt pick-up after cure and has a protective layer on the sealant interface with air.