Abstract: In a method of strengthening chemically a glass container comprising applying an aqueous solution of potassium salts to a soda-containing glass container to form a potassium salt adhered layer, holding at an ion exchange treatment temperature for a period of time sufficient, then cooling to room temperature and removing the residual potassium salts, the feature consists in using, as the aqueous solution of potassium salts, a concentrated aqueous solution containing a small amount of surfactant and a high concentration of mixed potassium salts consisting of potassium nitrate having a relatively low melting point and at least one potassium salt having a relatively high melting point selected from the group consisting of potassium chloride and potassium sulfate in such a proportion that 10 to 80% by weight of the potassium salts be present in solid phase, when heated at the ion exchange treatment temperature, to prevent the fused potassium salts from flowing off from the surfaces of the glass container, applying

Abstract: Thin-walled, light glass containers formed by the press and blow process may be strengthened by(1) exposing the internal surface of said containers to the action of an agent capable of decreasing the amount of extractable alkali from said surface at an elevated temperature immediately after the blowing process but before the annealing process;(2) passing the containers through the annealing station; and(3) subjecting the external and internal surfaces of said glass containers to a treatment of exchanging sodium ions in the surface portion with potassium ions to form a compressive stress layer in said surface portion.

Abstract: This invention relates to a chemical method of strengthening glass articles subjected to abrasion resistance treatment, which comprises (1) a first step of applying a metal oxide-forming compound to the surface of a heated glass article to form the corresponding metal oxide coating having a thickness of 50 to 130 Angstrom on the surface of the glass article, (2) a second step of causing to adhere, to the outer and inner surfaces of the glass article, a mixed solution of potassium chloride and potassium nitrate, having a potassium chloride to potassium nitrate ratio by weight of 85 to 45:15 to 55, or a mixed solution of potassium sulfate and potassium nitrate, having a potassium sulfate to potassium nitrate ratio by weight of 30 to 100:70 to 0, (3) a third step of holding the glass article at an elevated temperature below the strain point of the glass but as near the strain point as possible for a period of time sufficient to obtain a compressive stress layer having a depth of at least 10 microns and a compres