A process for applying an infra red reflecting coating on hot glass by directing onto a glass surface above 660°C a tin compound in the form of a finely divided solid which decomposes under the conditions of application to deposit a fluorine-containing tin oxide on the glass. The use of a high glass temperature above 660°C gives a product with increased infra red reflectivity and light transmission. The glass may be in the form of a ribbon e.g. of rolled glass, which is hot from the forming process.