AbstractSilicone films were equilibrated with special organosiloxanes in the presence of hexacholorocyclotriphosphatriene as catalyst in ethers as solvents. Thus, the hydrophobic silicone films developed a hydrophilic surface. This surface treatment does in no way reduce the oxygen permeability of the silicone films. The special organosiloxanes required for the equilibration were produced by addition of allyl compounds containing protected OH‐groups to siloxanes containing SiH‐groups, applying H2PtCl6as catalyst, and subsequent hydrolysis of the addition pro