Glass design via hybrid sol–gel materials

The development of dye-doped hybrid layers at the Fraunhofer-Institut für Silicatforschung (ISC) reveals a promising approach to very flexible glass design for a wide range of different glass types, e.g. soda lime glass, crystal glass or lead crystal glass. Transparent coloration was achieved by using commercial dyes soluble in aqueous–alcoholic solvent mixtures. A variety of organic and inorganic pigment mixtures could be incorporated, generating translucent and opaque coatings, respectively. Colourability of the ORMOCER® matrix is sufficient to adjust nearly any shade and intensity of a given colour pattern even at the low coating thicknesses of 5–20 μm which are characteristic for the inorganic–organic polymers. The coloured coatings may be imparted with additional functionalities. Thus low surface energy (down to 13 mN/m) coloured coatings were produced for transparent, translucent and opaque layers. The synthesis, processing and properties of the coloured, hybrid sol–gel coating materials are reviewed.