Liquid-crystalline medium

A process for the preparation of a window element, comprising

• providing a switchable optical cell which comprises a switchable layer interposed between a first transparent substrate and a second transparent substrate, wherein the switchable optical cell is electrically switchable, and wherein the switchable optical cell has a layer structure comprising, in sequence, the first transparent substrate, a first electrode layer, a first alignment layer, the switchable layer, a second alignment layer, a second transparent electrode layer, and the second transparent substrate,
• wherein the switchable layer comprises a liquid-crystalline medium having a negative dielectric anisotropy, a clearing point of greater than 140° C. to 170° C., and an optical anisotropy Δn in the range of from 0.075 to 0.1, and the switchable layer is a homeotropically aligned liquid crystal layer comprising the liquid-crystalline medium, wherein in the presence of an electric field the switchable layer has a twisted configuration or a supertwisted configuration, wherein the liquid-crystalline medium comprises three or more dichroic dyes, and wherein the switchable layer has a thickness in the range from 4 μm to 10 μm, and
• laminating the switchable optical cell to a third substrate via a thermoplastic interlayer arranged between the first or second transparent substrate of the switchable optical cell and the third substrate, wherein, during the laminating, heating to a temperature of 110° C. or more is carried out;
• and
• wherein the first transparent substrate and the second transparent substrate are made of plastic and are optically isotropic, and the third substrate is curved, made of glass, and is optically isotropic and transparent.