A composition containing the following components: (a) a polysiloxane having at least one alkenyl functional group and at least one alkoxy functional group; (b) a mercapto-functional polysiloxane with at least one mercapto functionality; (c) a silane crosslinker with at least two alkoxy groups per molecule; (d) a photoinitiator; (e) a combination of zirconium tetraalkoxylate and alkylacetoacetate at a mole ratio in a range of 1:1 to 1:4.