Abstract: Foldable apparatus comprise a foldable substrate comprising a substrate layer comprising a first major surface contacting a first inner surface area of a first portion. The first major surface of the substrate layer contacts a second inner surface area of a second portion. The first portion and the second portion are separated by a minimum distance. In aspects, the first portion and/or the second portion is directly bonded to the first major surface. In aspects, the substrate layer is chemically strengthened. In aspects, the first portion and/or the second portion are unstrengthened. Methods comprise contacting at least the first major surface of the substrate layer with a hydroxide-containing solution. Methods comprise forming a foldable substrate by disposing the first portion over the first major surface, disposing the second portion over the first major surface, and then heating the foldable substrate.

Abstract: Described herein are aqueous acidic glass etching solutions or media comprising HF and H2SO4, wherein HF is present in concentrations not exceeding about 1.3M. The etching solutions are used to treat glass articles such as thin glass sheets at above-ambient temperatures to etch slight thicknesses of surface glass therefrom, the etching solutions exhibiting improved stability against dissolved glass precipitation and rapid glass removal rates at slightly elevated temperatures.

Abstract: Described herein are aqueous acidic glass etching solutions or media comprising HF and H2SO4, wherein HF is present in concentrations not exceeding about 1.3M. The etching solutions are used to treat glass articles such as thin glass sheets at above-ambient temperatures to etch slight thicknesses of surface glass therefrom, the etching solutions exhibiting improved stability against dissolved glass precipitation and rapid glass removal rates at slightly elevated temperatures.