UV curable cycloaliphatic epoxy functionalized oligosiloxane resin is synthesized by non-hydrolytic sol–gel reaction for application in encapsulation of organic light emitting devices (OLEDs). The physical and chemical properties of polymerized cycloaliphatic epoxy hybrid materials (hybrimers) are easily tunable by controlling the precursors. A single hybrimer coating on a PET film is optically transparent and shows low permeability of up to 0.68 g m⁻² day⁻¹ per mil measured by a Ca degradation test. It is found that the permeability is influenced by the siloxane and epoxy network density, and the surface energy of the coating. An optimized hybrimer barrier coated film is applied to the encapsulation of an OLED with the aim of extending life-time.