Methods of manufacturing a glass-based article comprise: exposing an alkali-aluminosilicate glass-based substrate comprising opposing first and second surfaces defining a substrate thickness (t) to an ion exchange treatment to produce an ion exchanged glass-based substrate; and thereafter cooling the ion exchanged glass-based substrate in an environment having a starting temperature that is less than or equal to 200 C. and then reducing the temperature at a rate of greater than or equal to 3.3 C./minute to form the glass-based article.

A method of etching a substrate comprises: contacting a substrate having a thickness with an etchant disposed in a vessel for a period of time until the thickness has reduced by at least 2 m and at an average rate of 1 m per minute to 6.7 m per minute, the etchant having a temperature of 170 C. to 300 C. and comprising a molten mixture of two or more alkali hydroxides; and ceasing contacting the substrate with the etchant. The etchant in some instances comprises a molten mixture of NaOH and KOH. For example, the etchant in some instances includes a molten mixture of 24 wt. % to 72 wt. % NaOH, and 76 wt. % to 28 wt. % KOH. In some instances, the method alters the weight percentage of Na.sup.+, K.sup.+ and Li.sup.+ in the composition of the surface of the substrate by less than 1%.

Computer-implemented methods and apparatus are provided for predicting/estimating (i) a non-equilibrium viscosity for at least one given time point in a given temperature profile for a given glass composition, (ii) at least one temperature profile that will provide a given non-equilibrium viscosity for a given glass composition, or (iii) at least one glass composition that will provide a given non-equilibrium viscosity for a given time point in a given temperature profile. The methods and apparatus can be used to predict/estimate stress relaxation in a glass article during forming as well as compaction, stress relaxation, and/or thermal sag or thermal creep of a glass article when the article is subjected to one or more post-forming thermal treatments.

A method for forming a laminated glass article may include flowing a molten first glass composition having a first R.sub.2O concentration and a first fining agent with a first fining agent concentration. The method may also include flowing a molten second glass composition having a second R.sub.2O concentration less than the first R.sub.2O concentration of the first glass composition and a second fining agent with a second fining agent concentration that is greater than or equal to the first fining agent concentration of the first glass composition. The molten first glass composition may be contacted with the molten second glass composition to form an interface between the molten first glass composition and the molten second glass composition.

A cover glass of the present invention is characterized by including in a glass composition at least three or more components selected from SiO.sub.2, Al.sub.2O.sub.3, B.sub.2O.sub.3, Li.sub.2O, Na.sub.2O, K.sub.2O, MgO, CaO, BaO, TiO.sub.2, Y.sub.2O.sub.3, ZrO.sub.2, and P.sub.2O.sub.3, and having an X value of 7,400 or more calculated by the following equation. The X value is a value calculated by the equation X=61.1[SiO.sub.2]+174.3[Al.sub.2O.sub.3]+11.3[B.sub.2O.sub.3]+124.7[Li.sub.2O]5.2[Na.sub.2O]+2 26.7[K.sub.2O]+139.4[MgO]+117.5[CaO]+89.6[BaO]+191.8[TiO.sub.2]+226. 7[Y.sub.2O.sub.3]+157.9[ZrO.sub.2]42.2[P.sub.2O.sub.5].

Embodiments disclosed therein generally pertain to selectively strengthening glass. More particularly, techniques are described for selectively strengthening cover glass, which tends to be thin, for electronic devices, namely, portable electronic devices.

An article that includes: SiO.sub.2 from 40 mol % to 80 mol %; Al.sub.2O.sub.3 from 1 mol % to 15 mol %; B.sub.2O.sub.3 from 5 mol % to 50 mol %; WO.sub.3 from 1 mol % to 15 mol %; WO.sub.3 plus MoO.sub.3 from 1 mol % to 18 mol %; SnO.sub.2 from 0.01 mol % to 1 mol %; and R.sub.2O from 1.1 mol % to 16 mol %. The R.sub.2O is one or more of Li.sub.2O, Na.sub.2O, K.sub.2O, Rb.sub.2O and Cs.sub.2O. R.sub.2O minus Al.sub.2O.sub.3 ranges from +0.1 mol % to +4 mol %.

Embodiments disclosed therein generally pertain to selectively strengthening glass. More particularly, techniques are described for selectively strengthening cover glass, which tends to be thin, for electronic devices, namely, portable electronic devices.

An ion exchange tank is provided. The ion exchange tank includes a processing chamber and an additive chamber separated by a weir system, the weir system having a flow channel fluidly connecting the processing chamber to the additive chamber, wherein the flow is divided from the additive chamber by a first partition and divided from the processing chamber by a second partition, wherein the additive chamber comprises a solids-absorbing material disposed therein.

Methods and apparatuses for delivering and retaining solid chemicals in molten salt baths are provided, the chemicals may serve to reduce the lithium poisoning level of the molten salt bath. Methods and apparatuses are also provided for retaining sludge in a molten salt bath, allowing for removal of the sludge from the molten salt bath.