Abstract: This composition for treating the surface of a glass-ceramic, especially in plate form, flat glass or hollowware, or glass in the form of fibers, is able to be applied as a thin coating to said glass-ceramic or said glass.

Abstract: A method for cutting a glazing unit without applying a breaking force. The method applies a treatment to the glass sheet that generates stresses with a biaxial distribution, the stresses being such that the K factor is between 0.05 and 0.4 MPa·m1/2; the K factor being defined by K=[??z2·H(?z)·dz]1/2 in which z is a position in the thickness, ?z is intensity of the approximately isotropic biaxial stress at the position z, H(?z) is equal to 1 if ?z is greater than 0 and is equal to 0 if ?z is less than or equal to 0, with the convention that extension is denoted by positive values and compression by negative values. A subcrack deeper than 10 ?m is scored along the desired line of cutting, the subcrack reaching that region of the glazing in extension. The method allows cutting of glass, without breaking it, along curves with a small radius of curvature, or of glass strips of width similar to the thickness, or of frame shapes used as inserts in a flat field emission display.

Abstract: The subject of the invention is a process for treating a glass sheet which consists of a glass composition having a strain point above 540° C. and is intended for producing a display screen, the said process including at least one ion-exchange treatment on at least part of the surface of the glass sheet and a precontraction treatment.

Abstract: The subject of the invention is a glass composition intended to be converted into glass ribbon, comprising the constituents below in the following proportions by weight: SiO2 55-71% Al2O3 >2% MgO 4-11%, and > 8% if Al2O3 < 5% Na2O 9-16.5% K2O 4-10%.