COLORED GLASS ARTICLES HAVING IMPROVED MECHANICAL DURABILITY

Abstract

A colored glass article includes from 40 mol % to 70 mol % SiO.sub.2; from 8 mol % to 20 mol % Al.sub.2O.sub.3; from 1 mol % to 10 mol % B.sub.2O.sub.3; from 1 mol % to 20 mol % Li.sub.2O; from 1 mol % to 15 mol % Na.sub.2O; from 0 mol % to 8 mol % MgO; from 0 mol % to 5 mol % ZnO; and from 0.0005 mol % to 1 mol % Au. MgO+ZnO is from 0.1 mol % to 6 mol %.

Claims

1. A glass composition comprising: greater than or equal to 40 mol % and less than or equal to 70 mol % SiO.sub.2; greater than or equal to 8 mol % and less than or equal to 20 mol % Al.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 10 mol % B.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 20 mol % Li.sub.2O; greater than or equal to 1 mol % and less than or equal to 15 mol % Na.sub.2O; greater than or equal to 0 mol % and less than or equal to 6 mol % MgO; greater than or equal to 0 mol % and less than or equal to 5 mol % ZnO; and greater than or equal to 1×10.sup.−6 mol % mol % and less than or equal to 1 mol % Au, wherein: MgO+ZnO is greater than or equal to 0.1 mol % and less than or equal to 6 mol %.

2. The glass composition of claim 1, wherein MgO+ZnO is greater than or equal to 0.5 mol % and less than or equal to 5.5 mol %.

3. The glass composition of claim 1, wherein the glass composition comprises greater than or equal to 0.1 mol % and less than or equal to 5 mol % MgO.

4. The glass composition of claim 1, wherein the glass composition comprises greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.01 mol % Au.

5. The glass composition of claim 1, wherein R.sub.2O—Al.sub.2O.sub.3 is greater than or equal to −3 mol % and less than or equal to 2 mol %.

6. The glass composition of claim 1, wherein the glass composition comprises greater than or equal to 0.1 mol % and less than or equal to 2 mol % ZrO.sub.2.

7. The glass composition of claim 1, wherein 5.72*Al.sub.2O.sub.3 (mol %)−21.4*ZnO (mol %)−2.5*P.sub.2O.sub.5 (mol %)−35*Li.sub.2O (mol %)−16.6*B.sub.2O.sub.3 (mol %)−20.5*MgO (mol %)—23.3*Na.sub.2O (mol %)−27.9*SrO (mol %)−18.5*K.sub.2O (mol %)−26.3*CaO (mol %) is greater than −609 mol %.

8. The glass composition of claim 1, wherein the glass composition comprises greater than or equal to 0.01 mol % and less than or equal to 1 mol % SnO.sub.2.

9. The glass composition of claim 1, wherein the glass composition comprises greater than or equal to 0.1 mol % and less than or equal to 1 mol % K.sub.2O.

10. The glass composition of claim 1, wherein R.sub.2O is greater than or equal to 2 mol % and less than or equal to 35 mol %, wherein R.sub.2O is the sum of Li.sub.2O, Na.sub.2O, and K.sub.2O.

11. A colored glass article comprising: greater than or equal to 40 mol % and less than or equal to 70 mol % SiO.sub.2; greater than or equal to 8 mol % and less than or equal to 20 mol % Al.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 10 mol % B.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 20 mol % Li.sub.2O; greater than or equal to 1 mol % and less than or equal to 15 mol % Na.sub.2O; greater than or equal to 0 mol % and less than or equal to 6 mol % MgO; greater than or equal to 0 mol % and less than or equal to 5 mol % ZnO; and greater than or equal to 1×10.sup.−6 mol % and less than or equal to 1 mol % Au, wherein: MgO+ZnO is greater than or equal to 0.1 mol % and less than or equal to 6 mol %.

12. The colored glass article of claim 11, wherein the colored glass article has a transmittance color coordinate in the CIELAB color space as measured at an article thickness of 1.33 mm under F2 illumination and a 10° standard observer angle of: L* greater than or equal to 65 and less than or equal to 98; a* greater than or equal to −10 and less than or equal to 25; and b* greater than or equal to −20 and less than or equal to 5.

13. The colored glass article of claim 11, wherein the colored glass article has a thickness greater than or equal to 250 μm and less than or equal to 6 mm.

14. The colored glass article of claim 11, wherein the colored glass article is an ion-exchanged colored glass article.

15. The colored glass article of claim 11, wherein the ion-exchanged colored glass article has a depth of compression 3 μm or greater.

16. The colored glass article of claim 11, wherein the ion-exchanged colored glass article has a thickness “t” and a depth of compression greater than or equal to 0.15 t.

17. The colored glass article of claim 11, wherein the ion-exchanged colored glass article has a surface compressive stress greater than or equal to 300 MPa.

18. The colored glass article of claim 11, wherein the ion-exchanged colored glass article has a maximum central tension greater than or equal to 40 MPa.

19. A consumer electronic device, comprising: a housing having a front surface, a back surface, and side surfaces; and electrical components provided at least partially within the housing, the electrical components including at least a controller, a memory, and a display, the display being provided at or adjacent the front surface of the housing; wherein the housing comprises the colored glass article of claim 11.

20. A method of forming a colored glass article, the method comprising: heat treating a glass composition to form a glass article, the glass composition comprising: greater than or equal to 40 mol % and less than or equal to 70 mol % SiO.sub.2; greater than or equal to 8 mol % and less than or equal to 20 mol % Al.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 10 mol % B.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 20 mol % Li.sub.2O; greater than or equal to 1 mol % and less than or equal to 15 mol % Na.sub.2O; greater than or equal to 0 mol % and less than or equal to 6 mol % MgO; greater than or equal to 0 mol % and less than or equal to 5 mol % ZnO; and greater than or equal to 1×10.sup.−6 mol % and less than or equal to 1 mol % Au, wherein: MgO+ZnO is greater than or equal to 0.1 mol % and less than or equal to 6 mol %; and subjecting the glass article to a heat treatment cycle at a temperature greater than or equal to 500° C. and less than or equal to 800° C. and a duration greater than or equal to 0.25 hour and less than or equal to 24 hours to produced the colored glass article.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0118] FIG. 1 is a plan view of an electronic device incorporating any of the colored glass articles according to one or more embodiments described herein;

[0119] FIG. 2 is a perspective view of the electronic device of FIG. 1;

[0120] FIG. 3A is a plot of a* vs. b* CIELAB space (x-axis: a*; y-axis: b*) as a function of a heat treatment temperature of a colored glass article made from a glass composition according to one or more embodiments described herein;

[0121] FIG. 3B is a plot of a projected a* vs. L* CIELAB space (x-axis: a*; y-axis: L*) of the colored glass article of FIG. 3A;

[0122] FIG. 3C is a plot of a projected b* vs. L* CIELAB space (x-axis: b*; y-axis: L*) of the colored glass article of FIG. 3A;

[0123] FIG. 4A is a plot of a* vs. b* CIELAB space (x-axis: a*; y-axis: b*) as a function of a heat treatment temperature of a colored glass article made from a glass composition according to one or more embodiments described herein;

[0124] FIG. 4B is a plot of a projected a* vs. L* CIELAB space (x-axis: a*; y-axis: L*) of the colored glass article of FIG. 4A;

[0125] FIG. 4C is a plot of a projected b* vs. L* CIELAB space (x-axis: b*; y-axis: L*) of the colored glass article of FIG. 4A;

[0126] FIG. 5A is a plot of a* vs. b* CIELAB space (x-axis: a*; y-axis: b*) as a function of a heat treatment temperature of a colored glass article made from a glass composition according to one or more embodiments described herein;

[0127] FIG. 5B is a plot of a projected a* vs. L* CIELAB space (x-axis: a*; y-axis: L*) of the colored glass article of FIG. 5A;

[0128] FIG. 5C is a plot of a projected b* vs. L* CIELAB space (x-axis: b*; y-axis: L*) of the colored glass article of FIG. 5A;

[0129] FIG. 6A is a plot of a* vs. b* CIELAB space (x-axis: a*; y-axis: b*) as a function of a heat treatment temperature of a colored glass article made from a glass composition according to one or more embodiments described herein;

[0130] FIG. 6B is a plot of a projected a* vs. L* CIELAB space (x-axis: a*; y-axis: L*) of the colored glass article of FIG. 6A; and

[0131] FIG. 6C is a plot of a projected b* vs. L* CIELAB space (x-axis: b*; y-axis: L*) of the colored glass article of FIG. 6A.

DETAILED DESCRIPTION

[0132] Reference will now be made in detail to various embodiments of glass compositions and colored glass articles formed therefrom having a desired color. According to embodiments, a colored glass article includes greater than or equal to 40 mol % and less than or equal to 70 mol % SiO.sub.2; greater than or equal to 8 mol % and less than or equal to 20 mol % Al.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 10 mol % B.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 20 mol % Li.sub.2O; greater than or equal to 1 mol % and less than or equal to 15 mol % Na.sub.2O; greater than or equal to 0 mol % and less than or equal to 8 mol % MgO; greater than or equal to 0 mol % and less than or equal to 5 mol % ZnO; and greater than or equal to 0.0005 mol % and less than or equal to 1 mol % Au. MgO+ZnO is greater than or equal to 0.1 mol % and less than or equal to 6 mol %.

[0133] According to other embodiments, a colored glass article includes greater than or equal to 40 mol % and less than or equal to 70 mol % SiO.sub.2; greater than or equal to 8 mol % and less than or equal to 20 mol % Al.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 10 mol % B.sub.2O.sub.3; greater than or equal to 1 mol % and less than or equal to 20 mol % Li.sub.2O; greater than or equal to 1 mol % and less than or equal to 15 mol % Na.sub.2O; greater than or equal to 0 mol % and less than or equal to 6 mol % MgO; greater than or equal to 0 mol % and less than or equal to 5 mol % ZnO; and greater than or equal to 1×10.sup.−6 mol % and less than or equal to 1 mol % Au. MgO+ZnO is greater than or equal to 0.1 mol % and less than or equal to 6 mol %.

[0134] Various embodiments of colored glass articles and methods of making the same will be described herein with specific reference to the appended drawings.

[0135] Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0136] Directional terms as used herein—for example up, down, right, left, front, back, top, bottom—are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0137] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0138] As used herein, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0139] In the embodiments of the glass compositions and the resultant colored glass articles described herein, the concentrations of constituent components in oxide form (e.g., SiO.sub.2, Al.sub.2O.sub.3, and the like) are specified in mole percent (mol %) on an oxide basis, unless otherwise specified.

[0140] In embodiments of the glass compositions and the resultant colored glass articles described herein, the concentration of Au is specified in mole percent (mol %), unless otherwise specified.

[0141] In embodiments of the glass compositions and the resultant colored glass articles described herein, the concentration of a cation “M” is specified in mole percent (mol %), unless otherwise specified.

[0142] The terms “0 mol %,” “free,” and “substantially free,” when used to describe the concentration and/or absence of a particular constituent component in a glass composition and the resultant colored glass article, means that the constituent component is not intentionally added to the glass composition and the resultant colored glass article. However, the glass composition and the resultant colored glass article may contain traces of the constituent component as a contaminant or tramp in amounts of less than 0.01 mol %.

[0143] The term “fracture toughness,” as used herein, refers to the K.sub.Ic value, and is measured by the chevron notched short bar method. The chevron notched short bar (CNSB) method is disclosed in Reddy, K. P. R. et al, “Fracture Toughness Measurement of Glass and Ceramic Materials Using Chevron-Notched Specimens,” J. Am. Ceram. Soc., 71 [6], C-310-C-313 (1988) except that Y*m is calculated using equation 5 of Bubsey, R. T. et al., “Closed-Form Expressions for Crack-Mouth Displacement and Stress Intensity Factors for Chevron-Notched Short Bar and Short Rod Specimens Based on Experimental Compliance Measurements,” NASA Technical Memorandum 83796, pp. 1-30 (October 1992).

[0144] The viscosity of the glass composition, as described herein, is measured according to ASTM C965-96.

[0145] The term “melting point,” as used herein, refers to the temperature at which the viscosity of the glass composition is 200 poise.

[0146] The term “softening point,” as used herein, refers to the temperature at which the viscosity of the glass composition is 1×10.sup.76 poise. The softening point is measured according to the parallel plate viscosity method which measures the viscosity of inorganic glass from 10.sup.7 to 10.sup.9 poise as a function of temperature, similar to ASTM C1351M.

[0147] The terms “annealing point” as used herein, refer to the temperature at which the viscosity of the glass composition is 1×10.sup.13.18 poise.

[0148] The term “strain point,” as used herein, refers to the temperature at which the viscosity of the glass composition is 1×10.sup.14.68 poise.

[0149] The term “linear coefficient of thermal expansion” and “CTE,” as described herein, is measured in accordance with ASTM E228-85 over the temperature range of 25° C. to 300° C. and is expressed in terms of “×10.sup.−7/° C.” as an average over the temperature range.

[0150] The term “liquidus viscosity,” as used herein, refers to the viscosity of the glass composition at the onset of devitrification (i.e., at the liquidus temperature as determined with the gradient furnace method according to ASTM C829-81).

[0151] The term “liquidus temperature,” as used herein, refers to the temperature at which the glass composition begins to devitrify as determined with the gradient furnace method according to ASTM C829-81.

[0152] Surface compressive stress is measured with a surface stress meter (FSM) such as commercially available instruments such as the FSM-6000, manufactured by Orihara Industrial Co., Ltd. (Japan). Surface stress measurements rely upon the measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass article. SOC, in turn, is measured according to Procedure C (Glass Disc Method) described in ASTM standard C770-16, entitled “Standard Test Method for Measurement of Glass Stress-Optical Coefficient,” the contents of which are incorporated herein by reference in their entirety. Depth of compression (DOC) is also measured with the FSM. The maximum central tension (CT) values are measured using a scattered light polariscope (SCALP) technique known in the art.

[0153] The term “depth of compression” (DOC), as used herein, refers to the position in the article where compressive stress transitions to tensile stress.

[0154] The term “CIELAB color space,” as used herein, refers to a color space defined by the International Commission on Illumination (CIE) in 1976. It expresses color as three values: L* for the lightness from black (0) to white (100), a* from green (−) to red (+), and B* from blue (−) to yellow (+).

[0155] The term “color gamut,” as used herein, refers to the pallet of colors that may be achieved by the colored glass articles within the CIELAB color space.

[0156] The “optical transmission spectra,” as shown herein, were obtained using an Agilent Cary 60 spectrophotometer with a scan range of 250 nm to 800 nm, a scan step of 2 nm, a signal average of 0.5 s, and a spot size of 2 mm. The optical transmission data obtained were used to plot coordinates in the CIELAB color space as described in R. S. Berns, Billmeyer and Saltzman's Principles of Color Technology, 3rd. Ed., John Wiley & Sons, New York (2000).

[0157] Colorants have been added to conventional aluminosilicate glass compositions to achieve a colored glass article having a desired color and improved mechanical properties. For example, gold (Au) doped glass articles are red, orange, purple, or blue. However, simply including colorants in aluminosilicate glass compositions may not produce the desired color. For example, Au evaporates at temperatures greater than 1400° C. Conventional aluminosilicate glass compositions may have a melting point greater than 1500° C., which results in poor Au retention during processing. The low Au retention limits the color gamut that may be achieved and may, at most, result in a glass article having a faint red hue.

[0158] Disclosed herein are glass compositions and colored glass articles formed therefrom that mitigate the aforementioned problems such that Au may be added to aluminosilicate glass compositions to produce colored glass articles having the desired color while retaining the superior ion-exchangeability and drop performance of the colored glass articles. Specifically, the glass compositions disclosed herein improve Au retention by including MgO and/or ZnO. Increasing the retention of Au expands the color gamut that may be achieved by the resultant colored glass articles and helps lower the amount of Au needed to be batched, which significantly reduces batch costs. Moreover, the concentration of certain constituent components may be adjusted to achieve a desired color and to prevent formation of Au particles.

[0159] The glass compositions and colored glass articles described herein may be described as aluminoborosilicate glass compositions and colored glass articles and comprise SiO.sub.2, Al.sub.2O.sub.3, and B.sub.2O.sub.3. In addition to SiO.sub.2, Al.sub.2O.sub.3, and B.sub.2O.sub.3, the glass compositions and colored glass articles described herein include Au to produce colored glass articles having the desired color. The glass compositions and colored glass articles described herein also include alkali oxides, such as Li.sub.2O and Na.sub.2O, to enable the ion-exchangeability of the colored glass articles. The glass compositions and colored glass articles described herein further include MgO and/or ZnO to improve Au retention and produce colored glass articles having the desired color. Additionally, the difference between R.sub.2O and Al.sub.2O.sub.3 (i.e. R.sub.2O (mol %)— Al.sub.2O.sub.3 (mol %)) in the glass compositions and resultant colored glass articles described herein may be adjusted to produce a desired observable color (e.g., pink, purple, red, orange, or blue). Furthermore, the viscosity of the glass composition may be adjusted to prevent devitrification of the glass composition and formation of Au particles before melting that may limit the color gamut that may be achieved.

[0160] SiO.sub.2 is the primary glass former in the glass compositions described herein and may function to stabilize the network structure of the colored glass articles. The concentration of SiO.sub.2 in the glass compositions and resultant colored glass articles should be sufficiently high (e.g., greater than or equal to 40 mol %) to enhance the chemical durability of the glass composition and, in particular, the resistance of the glass composition to degradation upon exposure to acidic solutions, basic solutions, and in water. The amount of SiO.sub.2 may be limited (e.g., to less than or equal to 70 mol %) to control the melting point of the glass composition, as the melting point of pure SiO.sub.2 or high SiO.sub.2 glasses is undesirably high. Thus, limiting the concentration of SiO.sub.2 may aid in improving the meltability and the formability of the resultant colored glass article.

[0161] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 40 mol % and less than or equal to 70 mol % SiO.sub.2. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 45 mol % and less than or equal to 67 mol % SiO.sub.2. In embodiments, the concentration of SiO.sub.2 in the glass composition and the resultant colored glass article may be greater than or equal to 40 mol %, greater than or equal to 45 mol %, greater than or equal to 50 mol %, greater than or equal to 53 mol %, greater than or equal to 55 mol %, or even greater than or equal to 57 mol %. In embodiments, the concentration of SiO.sub.2 in the glass composition and the colored resultant glass article may be less than or equal to 70 mol %, less than or equal to 67 mol %, less than or equal to 65 mol %, less than or equal to 63 mol %, less than or equal to 62 mol %, less than or equal to 61 mol %, or even less than or equal to 60 mol %. In embodiments, the concentration of SiO.sub.2 in the glass composition and the resultant colored glass article may be greater than or equal to 40 mol % and less than or equal to 70 mol %, greater than or equal to 40 mol % and less than or equal to 67 mol %, greater than or equal to 40 mol % and less than or equal to 65 mol % greater than or equal to 40 mol % and less than or equal to 63 mol %, greater than or equal to 40 mol % and less than or equal to 62 mol %, greater than or equal to 40 mol % and less than or equal to 61 mol %, greater than or equal to 40 mol % and less than or equal to 60 mol %, greater than or equal to 45 mol % and less than or equal to 70 mol %, greater than or equal to 45 mol % and less than or equal to 67 mol %, greater than or equal to 45 mol % and less than or equal to 65 mol % greater than or equal to 45 mol % and less than or equal to 63 mol %, greater than or equal to 45 mol % and less than or equal to 62 mol %, greater than or equal to 45 mol % and less than or equal to 61 mol %, greater than or equal to 45 mol % and less than or equal to 60 mol %, greater than or equal to 50 mol % and less than or equal to 70 mol %, greater than or equal to 50 mol % and less than or equal to 67 mol %, greater than or equal to 50 mol % and less than or equal to 65 mol % greater than or equal to 50 mol % and less than or equal to 63 mol %, greater than or equal to 50 mol % and less than or equal to 62 mol %, greater than or equal to 50 mol % and less than or equal to 61 mol %, greater than or equal to 50 mol % and less than or equal to 60 mol %, greater than or equal to 53 mol % and less than or equal to 70 mol %, greater than or equal to 53 mol % and less than or equal to 67 mol %, greater than or equal to 53 mol % and less than or equal to 65 mol % greater than or equal to 53 mol % and less than or equal to 63 mol %, greater than or equal to 53 mol % and less than or equal to 62 mol %, greater than or equal to 53 mol % and less than or equal to 61 mol %, greater than or equal to 53 mol % and less than or equal to 60 mol %, greater than or equal to 55 mol % and less than or equal to 70 mol %, greater than or equal to 55 mol % and less than or equal to 67 mol %, greater than or equal to 55 mol % and less than or equal to 65 mol % greater than or equal to 55 mol % and less than or equal to 63 mol %, greater than or equal to 55 mol % and less than or equal to 62 mol %, greater than or equal to 55 mol % and less than or equal to 61 mol %, greater than or equal to 55 mol % and less than or equal to 60 mol %, greater than or equal to 57 mol % and less than or equal to 70 mol %, greater than or equal to 57 mol % and less than or equal to 67 mol %, greater than or equal to 57 mol % and less than or equal to 65 mol % greater than or equal to 57 mol % and less than or equal to 63 mol %, greater than or equal to 57 mol % and less than or equal to 62 mol %, greater than or equal to 57 mol % and less than or equal to 61 mol %, or even greater than or equal to 57 mol % and less than or equal to 60 mol %, or any and all sub-ranges formed from any of these endpoints.

[0162] Like SiO.sub.2, Al.sub.2O.sub.3 may also stabilize the glass network and additionally provides improved mechanical properties and chemical durability to the glass composition and the resultant colored glass article. The amount of Al.sub.2O.sub.3 may also be tailored to control the viscosity of the glass composition. Al.sub.2O.sub.3 may be included such that the resultant glass composition has the desired fracture toughness (e.g., greater than or equal to 0.7 MPa.Math.m.sup.1/2). However, if the amount of Al.sub.2O.sub.3 is too high (e.g., greater than 20 mol %), the viscosity of the melt may increase, thereby diminishing the formability of the colored glass article.

[0163] Accordingly, in embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 8 mol % and less than or equal to 20 mol % Al.sub.2O.sub.3. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 10 mol % and less than or equal to 18 mol % Al.sub.2O.sub.3. In embodiments, the concentration of Al.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to 8 mol %, greater than or equal to 10 mol %, greater than or equal to 12 mol %, greater than or equal to 12.5 mol %, greater than or equal to 13 mol %, greater than or equal to 13.5 mol %, or even greater than or equal to 14 mol %. In embodiments, the concentration of Al.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be less than or equal to 20 mol %, less than or equal to 18 mol %, less than or equal to 17.5 mol %, or even less than or equal to 17 mol %. In embodiments, the concentration of Al.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to 8 mol % and less than or equal to 20 mol %, greater than or equal to 8 mol % and less than or equal to 18 mol % greater than or equal to 8 mol % and less than or equal to 17.5 mol %, greater than or equal to 8 mol % and less than or equal to 17 mol %, greater than or equal to 10 mol % and less than or equal to 20 mol %, greater than or equal to 10 mol % and less than or equal to 18 mol % greater than or equal to 10 mol % and less than or equal to 17.5 mol %, greater than or equal to 10 mol % and less than or equal to 17 mol %, greater than or equal to 12 mol % and less than or equal to 20 mol %, greater than or equal to 12 mol % and less than or equal to 18 mol % greater than or equal to 12 mol % and less than or equal to 17.5 mol %, greater than or equal to 12 mol % and less than or equal to 17 mol %, greater than or equal to 12.5 mol % and less than or equal to 20 mol %, greater than or equal to 12.5 mol % and less than or equal to 18 mol % greater than or equal to 12.5 mol % and less than or equal to 17.5 mol %, greater than or equal to 12.5 mol % and less than or equal to 17 mol %, greater than or equal to 13 mol % and less than or equal to 20 mol %, greater than or equal to 13 mol % and less than or equal to 18 mol % greater than or equal to 13 mol % and less than or equal to 17.5 mol %, greater than or equal to 13 mol % and less than or equal to 17 mol %, greater than or equal to 13.5 mol % and less than or equal to 20 mol %, greater than or equal to 13.5 mol % and less than or equal to 18 mol % greater than or equal to 13.5 mol % and less than or equal to 17.5 mol %, greater than or equal to 13.5 mol % and less than or equal to 17 mol %, greater than or equal to 14 mol % and less than or equal to 20 mol %, greater than or equal to 14 mol % and less than or equal to 18 mol % greater than or equal to 14 mol % and less than or equal to 17.5 mol %, or even greater than or equal to 14 mol % and less than or equal to 17 mol %, or any and all sub-ranges formed from any of these endpoints.

[0164] B.sub.2O.sub.3 decreases the melting point of the glass composition, which may help improve Au retention. B.sub.2O.sub.3 may also improve the damage resistance of the resultant colored glass article. In addition, B.sub.2O.sub.3 is added to reduce the formation of non-bridging oxygen, the presence of which may reduce fracture toughness. The concentration of B.sub.2O.sub.3 should be sufficiently high (e.g., greater than or equal to 1 mol %) to reduce the melting point of the glass composition, improve the formability, and increase the fracture toughness of the colored glass article. However, if B.sub.2O.sub.3 is too high (e.g., greater than 10 mol %), the annealing point and strain point may decrease, which increases stress relaxation and reduces the overall strength of the colored glass article.

[0165] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 1 mol % and less than or equal to 10 mol % B.sub.2O.sub.3. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 2 mol % and less than or equal to 8 mol % B.sub.2O.sub.3. In embodiments, the concentration of B.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to 1 mol %, greater than or equal to 2 mol %, greater than or equal to 3 mol %, greater than or equal to 4 mol %, greater than or equal to 4.5 mol %, greater than or equal to 5 mol %, or even greater than or equal to 5.5 mol %. In embodiments, the concentration of B.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be less than or equal to 10 mol %, less than or equal to 9 mol %, less than or equal to 8 mol %, less than or equal to 7.5 mol %, less than or equal to 7 mol %, or even less than or equal to 6.5 mol %. In embodiments, the concentration of B.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to 1 mol % and less than or equal to 10 mol %, greater than or equal to 1 mol % and less than or equal to 9 mol %, greater than or equal to 1 mol % and less than or equal to 8 mol %, greater than or equal to 1 mol % and less than or equal to 7.5 mol %, greater than or equal to 1 mol % and less than or equal to 7 mol %, greater than or equal to 1 mol % and less than or equal to 6.5 mol %, greater than or equal to 2 mol % and less than or equal to 10 mol %, greater than or equal to 2 mol % and less than or equal to 9 mol %, greater than or equal to 2 mol % and less than or equal to 8 mol %, greater than or equal to 2 mol % and less than or equal to 7.5 mol %, greater than or equal to 2 mol % and less than or equal to 7 mol %, greater than or equal to 2 mol % and less than or equal to 6.5 mol %, greater than or equal to 3 mol % and less than or equal to 10 mol %, greater than or equal to 3 mol % and less than or equal to 9 mol %, greater than or equal to 3 mol % and less than or equal to 8 mol %, greater than or equal to 3 mol % and less than or equal to 7.5 mol %, greater than or equal to 3 mol % and less than or equal to 7 mol %, greater than or equal to 3 mol % and less than or equal to 6.5 mol %, greater than or equal to 4 mol % and less than or equal to 10 mol %, greater than or equal to 4 mol % and less than or equal to 9 mol %, greater than or equal to 4 mol % and less than or equal to 8 mol %, greater than or equal to 4 mol % and less than or equal to 7.5 mol %, greater than or equal to 4 mol % and less than or equal to 7 mol %, greater than or equal to 4 mol % and less than or equal to 6.5 mol %, greater than or equal to 4.5 mol % and less than or equal to 10 mol %, greater than or equal to 4.5 mol % and less than or equal to 9 mol %, greater than or equal to 4.5 mol % and less than or equal to 8 mol %, greater than or equal to 4.5 mol % and less than or equal to 7.5 mol %, greater than or equal to 4.5 mol % and less than or equal to 7 mol %, greater than or equal to 4.5 mol % and less than or equal to 6.5 mol %, greater than or equal to 5 mol % and less than or equal to 10 mol %, greater than or equal to 5 mol % and less than or equal to 9 mol %, greater than or equal to 5 mol % and less than or equal to 8 mol %, greater than or equal to 5 mol % and less than or equal to 7.5 mol %, greater than or equal to 5 mol % and less than or equal to 7 mol %, greater than or equal to 5 mol % and less than or equal to 6.5 mol %, greater than or equal to 5.5 mol % and less than or equal to 10 mol %, greater than or equal to 5.5 mol % and less than or equal to 9 mol %, greater than or equal to 5.5 mol % and less than or equal to 8 mol %, greater than or equal to 5.5 mol % and less than or equal to 7.5 mol %, greater than or equal to 5.5 mol % and less than or equal to 7 mol %, or even greater than or equal to 5.5 mol % and less than or equal to 6.5 mol %, or any and all sub-ranges formed from any of these endpoints.

[0166] As described hereinabove, the glass compositions and the resultant colored glass articles may contain alkali oxides, such as Li.sub.2O and Na.sub.2O, to enable the ion-exchangeability of the colored glass articles.

[0167] Li.sub.2O aids in the ion-exchangeability of the colored glass article and also reduces the softening point of the glass composition, thereby increasing the formability of the colored glass articles. In addition, Li.sub.2O decreases the melting point of the glass composition, which may help improve Au retention. The concentration of Li.sub.2O in the glass compositions and resultant colored glass articles should be sufficiently high (e.g., greater than or equal to 1 mol %) to reduce the melting point of the glass composition and achieve the desired maximum central tension (e.g., greater than or equal to 40 MPa). However, if the amount of Li.sub.2O is too high (e.g., greater than 20 mol %), the liquidus temperature may increase, thereby diminishing the manufacturability of the colored glass article.

[0168] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 1 mol % and less than or equal to 20 mol % Li.sub.2O. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 3 mol % and less than or equal to 17 mol % Li.sub.2O. In embodiments, the concentration of Li.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 1 mol %, greater than or equal to 3 mol %, greater than or equal to 5 mol %, greater than or equal to 7 mol %, greater than or equal to 7.5 mol %, greater than or equal to 8 mol %, greater than or equal to 8.5 mol %, or even greater than or equal to 9 mol %. In embodiments, the concentration of Li.sub.2O in the glass composition and the resultant colored glass article may be less than or equal to 20 mol %, less than or equal to 17 mol %, less than or equal to 15 mol %, less than or equal to 13 mol %, less than or equal to 12.5 mol %, less than or equal to 12 mol %, less than or equal to 11.5 mol %, or even less than or equal to 11 mol %. In embodiments, the concentration of Li.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 1 mol % and less than or equal to 20 mol %, greater than or equal to 1 mol % and less than or equal to 17 mol %, greater than or equal to 1 mol % and less than or equal to 15 mol %, greater than or equal to 1 mol % and less than or equal to 13 mol %, greater than or equal to 1 mol % and less than or equal to 12.5 mol %, greater than or equal to 1 mol % and less than or equal to 12 mol %, greater than or equal to 1 mol % and less than or equal 11.5 mol %, greater than or equal to 1 mol % and less than or equal to 11 mol %, greater than or equal to 3 mol % and less than or equal to 20 mol %, greater than or equal to 3 mol % and less than or equal to 17 mol %, greater than or equal to 3 mol % and less than or equal to 15 mol %, greater than or equal to 3 mol % and less than or equal to 13 mol %, greater than or equal to 3 mol % and less than or equal to 12.5 mol %, greater than or equal to 3 mol % and less than or equal to 12 mol %, greater than or equal to 3 mol % and less than or equal 11.5 mol %, greater than or equal to 3 mol % and less than or equal to 11 mol %, greater than or equal to 5 mol % and less than or equal to 20 mol %, greater than or equal to 5 mol % and less than or equal to 17 mol %, greater than or equal to 5 mol % and less than or equal to 15 mol %, greater than or equal to 5 mol % and less than or equal to 13 mol %, greater than or equal to 5 mol % and less than or equal to 12.5 mol %, greater than or equal to 5 mol % and less than or equal to 12 mol %, greater than or equal to 5 mol % and less than or equal 11.5 mol %, greater than or equal to 5 mol % and less than or equal to 11 mol %, greater than or equal to 7 mol % and less than or equal to 20 mol %, greater than or equal to 7 mol % and less than or equal to 17 mol %, greater than or equal to 7 mol % and less than or equal to 15 mol %, greater than or equal to 7 mol % and less than or equal to 13 mol %, greater than or equal to 7 mol % and less than or equal to 12.5 mol %, greater than or equal to 7 mol % and less than or equal to 12 mol %, greater than or equal to 7 mol % and less than or equal 11.5 mol %, greater than or equal to 7 mol % and less than or equal to 11 mol %, greater than or equal to 7.5 mol % and less than or equal to 20 mol %, greater than or equal to 7.5 mol % and less than or equal to 17 mol %, greater than or equal to 7.5 mol % and less than or equal to 15 mol %, greater than or equal to 7.5 mol % and less than or equal to 13 mol %, greater than or equal to 7.5 mol % and less than or equal to 12.5 mol %, greater than or equal to 7.5 mol % and less than or equal to 12 mol %, greater than or equal to 7.5 mol % and less than or equal 11.5 mol %, greater than or equal to 7.5 mol % and less than or equal to 11 mol %, greater than or equal to 8 mol % and less than or equal to 20 mol %, greater than or equal to 8 mol % and less than or equal to 17 mol %, greater than or equal to 8 mol % and less than or equal to 15 mol %, greater than or equal to 8 mol % and less than or equal to 13 mol %, greater than or equal to 8 mol % and less than or equal to 12.5 mol %, greater than or equal to 8 mol % and less than or equal to 12 mol %, greater than or equal to 8 mol % and less than or equal 11.5 mol %, greater than or equal to 8 mol % and less than or equal to 11 mol %, greater than or equal to 8.5 mol % and less than or equal to 20 mol %, greater than or equal to 8.5 mol % and less than or equal to 17 mol %, greater than or equal to 8.5 mol % and less than or equal to 15 mol %, greater than or equal to 8.5 mol % and less than or equal to 13 mol %, greater than or equal to 8.5 mol % and less than or equal to 12.5 mol %, greater than or equal to 8.5 mol % and less than or equal to 12 mol %, greater than or equal to 8.5 mol % and less than or equal 11.5 mol %, greater than or equal to 8.5 mol % and less than or equal to 11 mol %, greater than or equal to 9 mol % and less than or equal to 20 mol %, greater than or equal to 9 mol % and less than or equal to 17 mol %, greater than or equal to 9 mol % and less than or equal to 15 mol %, greater than or equal to 9 mol % and less than or equal to 13 mol %, greater than or equal to 9 mol % and less than or equal to 12.5 mol %, greater than or equal to 9 mol % and less than or equal to 12 mol %, greater than or equal to 9 mol % and less than or equal 11.5 mol %, or even greater than or equal to 9 mol % and less than or equal to 11 mol %, or any and all sub-ranges formed from any of these endpoints.

[0169] Na.sub.2O improves diffusivity of alkali ions in the glass and thereby reduces ion-exchange time and helps achieve the desired surface compressive stress (e.g., greater than or equal to 300 MPa). Na.sub.2O also improves formability of the colored glass article. In addition, Na.sub.2O decreases the melting point of the glass composition, which may help improve Au retention. However, if too much Na.sub.2O is added to the glass composition, the melting point may be too low. As such, in embodiments, the concentration of Li.sub.2O present in the glass composition and the resultant colored glass article may be greater than the concentration of Na.sub.2O present in the glass composition and the resultant colored glass article.

[0170] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 1 mol % and less than or equal to 15 mol % Na.sub.2O. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 2 mol % and less than or equal to 10 mol % Na.sub.2O. In embodiments, the concentration of Na.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 1 mol %, greater than or equal to 2 mol %, greater than or equal to 3 mol %, greater than or equal to 3.5 mol %, greater than or equal to 4 mol %, or even greater than or equal to 4.5 mol %. In embodiments, the concentration of Na.sub.2O in the glass composition and the resultant colored glass article may be less than or equal to 15 mol %, less than or equal to 10 mol %, less than or equal to 8 mol %, less than or equal to 7.5 mol %, less than or equal to less than or equal to 7 mol %, less than or equal to 6.5 mol %, less than or equal to 6 mol %, or even less than or equal to 5.5 mol %. In embodiments, the concentration of Na.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 1 mol % and less than or equal to 15 mol %, greater than or equal to 1 and less than or equal to 10 mol %, greater than or equal to 1 mol % and less than or equal to 8 mol %, greater than or equal to 1 mol % and less than or equal to 7.5 mol %, greater than or equal to 1 mol % and less than or equal to 7 mol %, greater than or equal to 1 mol % and less than or equal to 6.5 mol %, greater than or equal to 1 mol % and less than or equal to 6 mol %, greater than or equal to 1 mol % and less than or equal to 5.5 mol %, greater than or equal to 2 mol % and less than or equal to 15 mol %, greater than or equal to 2 and less than or equal to 10 mol %, greater than or equal to 2 mol % and less than or equal to 8 mol %, greater than or equal to 2 mol % and less than or equal to 7.5 mol %, greater than or equal to 2 mol % and less than or equal to 7 mol %, greater than or equal to 2 mol % and less than or equal to 6.5 mol %, greater than or equal to 2 mol % and less than or equal to 6 mol %, greater than or equal to 2 mol % and less than or equal to 5.5 mol %, greater than or equal to 3 mol % and less than or equal to 15 mol %, greater than or equal to 3 and less than or equal to 10 mol %, greater than or equal to 3 mol % and less than or equal to 8 mol %, greater than or equal to 3 mol % and less than or equal to 7.5 mol %, greater than or equal to 3 mol % and less than or equal to 7 mol %, greater than or equal to 3 mol % and less than or equal to 6.5 mol %, greater than or equal to 3 mol % and less than or equal to 6 mol %, greater than or equal to 3 mol % and less than or equal to 5.5 mol %, greater than or equal to 3.5 mol % and less than or equal to 15 mol %, greater than or equal to 3.5 and less than or equal to 10 mol %, greater than or equal to 3.5 mol % and less than or equal to 8 mol %, greater than or equal to 3.5 mol % and less than or equal to 7.5 mol %, greater than or equal to 3.5 mol % and less than or equal to 7 mol %, greater than or equal to 3.5 mol % and less than or equal to 6.5 mol %, greater than or equal to 3.5 mol % and less than or equal to 6 mol %, greater than or equal to 3.5 mol % and less than or equal to 5.5 mol %, greater than or equal to 4 mol % and less than or equal to 15 mol %, greater than or equal to 4 and less than or equal to 10 mol %, greater than or equal to 4 mol % and less than or equal to 8 mol %, greater than or equal to 4 mol % and less than or equal to 7.5 mol %, greater than or equal to 4 mol % and less than or equal to 7 mol %, greater than or equal to 4 mol % and less than or equal to 6.5 mol %, greater than or equal to 4 mol % and less than or equal to 6 mol %, greater than or equal to 4 mol % and less than or equal to 5.5 mol %, greater than or equal to 4.5 mol % and less than or equal to 15 mol %, greater than or equal to 4.5 and less than or equal to 10 mol %, greater than or equal to 4.5 mol % and less than or equal to 8 mol %, greater than or equal to 4.5 mol % and less than or equal to 7.5 mol %, greater than or equal to 4.5 mol % and less than or equal to 7 mol %, greater than or equal to 4.5 mol % and less than or equal to 6.5 mol %, greater than or equal to 4.5 mol % and less than or equal to 6 mol %, or even greater than or equal to 4.5 mol % and less than or equal to 5.5 mol %, or any and all sub-ranges formed from any of these endpoints.

[0171] The glass compositions and the resultant colored glass articles described herein may optionally further comprise alkali metal oxides other than Li.sub.2O and Na.sub.2O, such as K.sub.2O. K.sub.2O, when included, promotes ion-exchange and may increase the depth of compression and decrease the melting point to improve the formability of the colored glass article. However, adding too much K.sub.2O may cause the surface compressive stress and melting point to be too low. Accordingly, in embodiments, the amount of K.sub.2O added to the glass composition may be limited.

[0172] In embodiments, the glass composition and the resultant colored glass article may optionally comprise greater than or equal to 0.1 mol % and less than or equal to 1 mol % K.sub.2O. In embodiments, the concentration of K.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol %, greater than or equal to 0.1 mol %, or even greater than or equal to 0.2 mol %. In embodiments, the concentration of K.sub.2O in the glass composition and the resultant colored glass article may be less than or equal to 1 mol %, less than or equal to 0.5 mol %, or even less than or equal to 0.5 mol %. In embodiments, the concentration of K.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0 mol % and less than or equal to 0.7 mol %, greater than or equal to 0 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.1 mol % and less than or equal to 1 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.7 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.2 mol % and less than or equal to 1 mol %, greater than or equal to 0.2 mol % and less than or equal to 0.7 mol %, or even greater than or equal to 0.2 mol % and less than or equal to 0.5 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of K.sub.2O.

[0173] The sum of all alkali oxides is expressed herein as R.sub.2O. Specifically, R.sub.2O is the sum (in mol %) of Li.sub.2O, Na.sub.2O, and K.sub.2O present in the glass composition and the resultant colored glass article (i.e., R.sub.2O=Li.sub.2O (mol %)+Na.sub.2O (mol %)+K.sub.2O (mol %). Like B.sub.2O.sub.3, the alkali oxides aid in decreasing the softening point and molding temperature of the glass composition, thereby offsetting the increase in the softening point and molding temperature of the glass composition due to higher amounts of SiO.sub.2 in the glass composition, for example. The softening point and molding temperature may be further reduced by including combinations of alkali oxides (e.g., two or more alkali oxides) in the glass composition, a phenomenon referred to as the “mixed alkali effect.” However, it has been found that if the amount of alkali oxide is too high, the average coefficient of thermal expansion of the glass composition increases to greater than 100×10.sup.−7/° C., which may be undesirable.

[0174] In embodiments, the concentration of R.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 2 mol % and less than or equal to 35 mol %. In embodiments, the concentration of R.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 2 mol %, greater than or equal to 4 mol %, greater than 6 mol %, greater than or equal to 8 mol %, greater than or equal to 10 mol %, greater than or equal to 12 mol %, or even greater than or equal to 14 mol %. In embodiments, the concentration of R.sub.2O in the glass composition and the resultant colored glass article may be less than or equal to 35 mol %, less than or equal to 30 mol %, less than or equal to 25 mol %, less than or equal to 20 mol %, less than or equal to 19 mol %, less than or equal to 18 mol %, less than or equal to 17 mol %, or even less than or equal to 16 mol %. In embodiments, the concentration of R.sub.2O in the glass composition and the resultant colored glass article may be greater than or equal to 2 mol % and less than or equal to 35 mol %, greater than or equal to 2 mol % and less than or equal to 30 mol %, greater than or equal to 2 mol % and less than or equal to 25 mol %, greater than or equal to 2 mol % and less than or equal to 20 mol %, greater than or equal to 2 mol % and less than or equal to 19 mol %, greater than or equal to 2 mol % and less than or equal to 18 mol %, greater than or equal to 2 mol % and less than or equal to 17 mol %, greater than or equal to 2 mol % and less than or equal to 16 mol %, greater than or equal to 4 mol % and less than or equal to 35 mol %, greater than or equal to 4 mol % and less than or equal to 30 mol %, greater than or equal to 4 mol % and less than or equal to 25 mol %, greater than or equal to 4 mol % and less than or equal to 20 mol %, greater than or equal to 4 mol % and less than or equal to 19 mol %, greater than or equal to 4 mol % and less than or equal to 18 mol %, greater than or equal to 4 mol % and less than or equal to 17 mol %, greater than or equal to 4 mol % and less than or equal to 16 mol %, greater than or equal to 6 mol % and less than or equal to 35 mol %, greater than or equal to 6 mol % and less than or equal to 30 mol %, greater than or equal to 6 mol % and less than or equal to 25 mol %, greater than or equal to 6 mol % and less than or equal to 20 mol %, greater than or equal to 6 mol % and less than or equal to 19 mol %, greater than or equal to 6 mol % and less than or equal to 18 mol %, greater than or equal to 6 mol % and less than or equal to 17 mol %, greater than or equal to 6 mol % and less than or equal to 16 mol %, greater than or equal to 8 mol % and less than or equal to 35 mol %, greater than or equal to 8 mol % and less than or equal to 30 mol %, greater than or equal to 8 mol % and less than or equal to 25 mol %, greater than or equal to 8 mol % and less than or equal to 20 mol %, greater than or equal to 8 mol % and less than or equal to 19 mol %, greater than or equal to 8 mol % and less than or equal to 18 mol %, greater than or equal to 8 mol % and less than or equal to 17 mol %, greater than or equal to 8 mol % and less than or equal to 16 mol %, greater than or equal to 10 mol % and less than or equal to 35 mol %, greater than or equal to 10 mol % and less than or equal to 30 mol %, greater than or equal to 10 mol % and less than or equal to 25 mol %, greater than or equal to 10 mol % and less than or equal to 20 mol %, greater than or equal to 10 mol % and less than or equal to 19 mol %, greater than or equal to 10 mol % and less than or equal to 18 mol %, greater than or equal to 10 mol % and less than or equal to 17 mol %, greater than or equal to 10 mol % and less than or equal to 16 mol %, greater than or equal to 12 mol % and less than or equal to 35 mol %, greater than or equal to 12 mol % and less than or equal to 30 mol %, greater than or equal to 12 mol % and less than or equal to 25 mol %, greater than or equal to 12 mol % and less than or equal to 20 mol %, greater than or equal to 12 mol % and less than or equal to 19 mol %, greater than or equal to 12 mol % and less than or equal to 18 mol %, greater than or equal to 12 mol % and less than or equal to 17 mol %, greater than or equal to 12 mol % and less than or equal to 16 mol %, greater than or equal to 14 mol % and less than or equal to 35 mol %, greater than or equal to 14 mol % and less than or equal to 30 mol %, greater than or equal to 14 mol % and less than or equal to 25 mol %, greater than or equal to 14 mol % and less than or equal to 20 mol %, greater than or equal to 14 mol % and less than or equal to 19 mol %, greater than or equal to 14 mol % and less than or equal to 18 mol %, greater than or equal to 14 mol % and less than or equal to 17 mol %, or even greater than or equal to 14 mol % and less than or equal to 16 mol %, or any and all sub-ranges formed from any of these endpoints.

[0175] In embodiments, the difference between R.sub.2O and Al.sub.2O.sub.3 (i.e. R.sub.2O (mol %)— Al.sub.2O.sub.3 (mol %)) in the glass composition may be adjusted to produce a desired observable color (e.g., pink, purple, red, orange, or blue). Along with the temperature and time of the heat treatment, the analyzed R.sub.2O—Al.sub.2O.sub.3 of the resultant colored glass article may correlate with the observable color of the colored glass article after heat treatment. In embodiments, R.sub.2O—Al.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to −3 mol % and less than or equal to 2 mol %. In embodiments, R.sub.2O—Al.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to −3 mol %, greater than or equal to −2.5, greater than or equal to −2, or even greater than or equal to −1.5. In embodiments, R.sub.2O—Al.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be less than or equal to 2 mol %, less than or equal to 1.5 mol %, less than or equal to 1 mol %, or even less than or equal to 0.5 mol %. In embodiments, R.sub.2O—Al.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to −3 mol % and less than or equal to 2 mol %, greater than or equal to −3 mol % and less than or equal to 1.5 mol %, greater than or equal to −3 mol % and less than or equal to 1 mol %, greater than or equal to −3 mol % and less than or equal to 0.5 mol %, greater than or equal to −2.5 mol % and less than or equal to 2 mol %, greater than or equal to −2.5 mol % and less than or equal to 1.5 mol %, greater than or equal to −2.5 mol % and less than or equal to 1 mol %, greater than or equal to −2.5 mol % and less than or equal to 0.5 mol %, greater than or equal to −2 mol % and less than or equal to 2 mol %, greater than or equal to −2 mol % and less than or equal to 1.5 mol %, greater than or equal to −2 mol % and less than or equal to 1 mol %, greater than or equal to −2 mol % and less than or equal to 0.5 mol %, greater than or equal to −1.5 mol % and less than or equal to 2 mol %, greater than or equal to −1.5 mol % and less than or equal to 1.5 mol %, greater than or equal to −1.5 mol % and less than or equal to 1 mol %, or even greater than or equal to −1.5 mol % and less than or equal to 0.5 mol %, or any and all sub-ranges formed from any of these endpoints.

[0176] The glass compositions and the resultant colored glass articles described herein further include MgO and/or ZnO to improve Au retention by lowering the melting point of the glass composition. Decreasing the melting point of the glass composition may help improve Au retention because the glass compositions may be melted at relatively lower temperatures and Au evaporation may be reduced. While not wishing to be bound by theory, it is also believed that partially replacing Li.sub.2O and/or Na.sub.2O with MgO and/or ZnO may also help improve Au retention. Specifically, Li.sub.2O and/or Na.sub.2O is included in the batch glass composition as lithium carbonate and sodium carbonate, respectively. Upon melting the glass composition, carbonate gas is released from the glass composition. Au escapes from the glass composition within the carbonate gas. Therefore, the improved Au retention may be due to the reduced amount of carbonate.

[0177] Accordingly, in embodiments, the sum (in mol %) of MgO and ZnO present in the glass composition and the resultant colored glass article (i.e., MgO (mol %)+ZnO (mol %)) may be greater than or equal to 0.1 mol % and less than or equal to 6 mol %. In embodiments, the sum of MgO and ZnO in the glass composition and the resultant colored glass article may be greater than or equal to 0.5 mol % and less than or equal to 5.5 mol %. In embodiments, the sum of MgO and ZnO in the glass composition and the resultant colored glass article may be greater than or equal to 0.1 mol %, greater than or equal to 0.5 mol %, greater than or equal to 1 mol %, greater than or equal to 1.5 mol %, greater than or equal to 2 mol %, greater than or equal to 2.5 mol %, greater than or equal to 3 mol %, or even greater than or equal to 3.5 mol %. In embodiments, the sum of MgO and ZnO in the glass composition and the resultant colored glass article may be less than or equal to 6 mol %, less than or equal to 5.5 mol %, less than or equal to 5 mol %, or even less than or equal to 4.5 mol %. In embodiments, the sum of MgO and ZnO in the glass composition and the resultant colored glass article may be greater than or equal to 0.1 mol % and less than or equal to 6 mol %, greater than or equal to 0.1 mol % and less than or equal to 5.5 mol %, greater than or equal to 0.1 mol % and less than or equal to 5 mol %, greater than or equal to 0.1 mol % and less than or equal to 4.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 6 mol %, greater than or equal to 0.5 mol % and less than or equal to 5.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 5 mol %, greater than or equal to 0.5 mol % and less than or equal to 4.5 mol %, greater than or equal to 1 mol % and less than or equal to 6 mol %, greater than or equal to 1 mol % and less than or equal to 5.5 mol %, greater than or equal to 1 mol % and less than or equal to 5 mol %, greater than or equal to 1 mol % and less than or equal to 4.5 mol %, greater than or equal to 1.5 mol % and less than or equal to 6 mol %, greater than or equal to 1.5 mol % and less than or equal to 5.5 mol %, greater than or equal to 1.5 mol % and less than or equal to 5 mol %, greater than or equal to 1.5 mol % and less than or equal to 4.5 mol %, greater than or equal to 2 mol % and less than or equal to 6 mol %, greater than or equal to 2 mol % and less than or equal to 5.5 mol %, greater than or equal to 2 mol % and less than or equal to 5 mol %, greater than or equal to 2 mol % and less than or equal to 4.5 mol %, greater than or equal to 2.5 mol % and less than or equal to 6 mol %, greater than or equal to 2.5 mol % and less than or equal to 5.5 mol %, greater than or equal to 2.5 mol % and less than or equal to 5 mol %, greater than or equal to 2.5 mol % and less than or equal to 4.5 mol %, greater than or equal to 3 mol % and less than or equal to 6 mol %, greater than or equal to 3 mol % and less than or equal to 5.5 mol %, greater than or equal to 3 mol % and less than or equal to 5 mol %, greater than or equal to 3 mol % and less than or equal to 4.5 mol %, greater than or equal to 3.5 mol % and less than or equal to 6 mol %, greater than or equal to 3.5 mol % and less than or equal to 5.5 mol %, greater than or equal to 3.5 mol % and less than or equal to 5 mol %, or even greater than or equal to 3.5 mol % and less than or equal to 4.5 mol %, or any and all sub-ranges formed from any of these endpoints.

[0178] In addition to improving Au retention, MgO lowers the viscosity of the glass compositions, which enhances the formability, the strain point, and the Young's modulus, and may improve ion-exchangeability. However, when too much MgO is added to the glass composition, the diffusivity of sodium and potassium ions in the glass composition decreases which, in turn, adversely impacts the ion-exchange performance (i.e., the ability to ion-exchange) of the resultant colored glass article.

[0179] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0 mol % and less than or equal to 8 mol % MgO. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.5 mol % and less than or equal to 7 mol % MgO. In embodiments, the concentration of MgO in the glass composition may be greater than or equal to 0 mol %, greater than or equal to 0.5 mol %, greater than or equal to 1 mol %, greater than or equal to 1.5 mol %, greater than or equal to 2 mol %, or even greater than or equal to 2.5 mol %. In embodiments, the concentration of MgO in the glass composition may be less than or equal to 8 mol %, less than or equal to 7 mol %, less than or equal to 6 mol %, less than or equal to 5.5 mol %, less than or equal to 5 mol %, less than or equal to 4.5 mol %, less than or equal to 4 mol %, or even less than or equal to 3.5 mol %. In embodiments, the concentration of MgO in the glass composition may be greater than or equal to 0 mol % and less than or equal to 8 mol %, greater than or equal to 0 mol % and less than or equal to 7 mol %, greater than or equal to 0 mol % and less than or equal to 6 mol %, greater than or equal to 0 mol % and less than or equal to 5.5 mol %, greater than or equal to 0 mol % and less than or equal to 5 mol %, greater than or equal to 0 mol % and less than or equal to 4.5 mol %, greater than or equal to 0 mol % and less than or equal to 4 mol %, greater than or equal to 0 mol % and less than or equal to 3.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 8 mol %, greater than or equal to 0.5 mol % and less than or equal to 7 mol %, greater than or equal to 0.5 mol % and less than or equal to 6 mol %, greater than or equal to 0.5 mol % and less than or equal to 5.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 5 mol %, greater than or equal to 0.5 mol % and less than or equal to 4.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 4 mol %, greater than or equal to 0.5 mol % and less than or equal to 3.5 mol %, greater than or equal to 1 mol % and less than or equal to 8 mol %, greater than or equal to 1 mol % and less than or equal to 7 mol %, greater than or equal to 1 mol % and less than or equal to 6 mol %, greater than or equal to 1 mol % and less than or equal to 5.5 mol %, greater than or equal to 1 mol % and less than or equal to 5 mol %, greater than or equal to 1 mol % and less than or equal to 4.5 mol %, greater than or equal to 1 mol % and less than or equal to 4 mol %, greater than or equal to 1 mol % and less than or equal to 3.5 mol %, greater than or equal to 1.5 mol % and less than or equal to 8 mol %, greater than or equal to 1.5 mol % and less than or equal to 7 mol %, greater than or equal to 1.5 mol % and less than or equal to 6 mol %, greater than or equal to 1.5 mol % and less than or equal to 5.5 mol %, greater than or equal to 1.5 mol % and less than or equal to 5 mol %, greater than or equal to 1.5 mol % and less than or equal to 4.5 mol %, greater than or equal to 1.5 mol % and less than or equal to 4 mol %, greater than or equal to 1.5 mol % and less than or equal to 3.5 mol %, greater than or equal to 2 mol % and less than or equal to 8 mol %, greater than or equal to 2 mol % and less than or equal to 7 mol %, greater than or equal to 2 mol % and less than or equal to 6 mol %, greater than or equal to 2 mol % and less than or equal to 5.5 mol %, greater than or equal to 2 mol % and less than or equal to 5 mol %, greater than or equal to 2 mol % and less than or equal to 4.5 mol %, greater than or equal to 2 mol % and less than or equal to 4 mol %, greater than or equal to 2 mol % and less than or equal to 3.5 mol %, greater than or equal to 0 mol % and less than or equal to 8 mol %, greater than or equal to 2.5 mol % and less than or equal to 7 mol %, greater than or equal to 2.5 mol % and less than or equal to 6 mol %, greater than or equal to 2.5 mol % and less than or equal to 5.5 mol %, greater than or equal to 2.5 mol % and less than or equal to 5 mol %, greater than or equal to 2.5 mol % and less than or equal to 4.5 mol %, greater than or equal to 2.5 mol % and less than or equal to 4 mol %, or even greater than or equal to 2.5 mol % and less than or equal to 3.5 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of MgO.

[0180] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0 mol % and less than or equal to 6 mol % MgO. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.1 mol % and less than or equal to 5 mol % MgO. In embodiments, the concentration of MgO in the glass composition may be greater than or equal to 0 mol %, greater than or equal to 0.1 mol %, or even greater than or equal to 0.5 mol %. In embodiments, the concentration of MgO in the glass composition may be less than or equal to 6 mol %, less than or equal to 5 mol %, less than or equal to 4 mol %, less than or equal to 3 mol %, less than or equal to 2 mol %, or even less than or equal to 1 mol %. In embodiments, the concentration of MgO in the glass composition may be greater than or equal to 0 mol % and less than or equal to 6 mol %, greater than or equal to 0 mol % and less than or equal to 5 mol %, greater than or equal to 0 mol % and less than or equal to 4 mol %, greater than or equal to 0 mol % and less than or equal to 3 mol %, greater than or equal to 0 mol % and less than or equal to 2 mol %, greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0.1 mol % and less than or equal to 6 mol %, greater than or equal to 0.1 mol % and less than or equal to 5 mol %, greater than or equal to 0.1 mol % and less than or equal to 4 mol %, greater than or equal to 0.1 mol % and less than or equal to 3 mol %, greater than or equal to 0.1 mol % and less than or equal to 2 mol %, greater than or equal to 0.1 mol % and less than or equal to 1 mol %, greater than or equal to 0.5 mol % and less than or equal to 6 mol %, greater than or equal to 0.5 mol % and less than or equal to 5 mol %, greater than or equal to 0.5 mol % and less than or equal to 4 mol %, greater than or equal to 0.5 mol % and less than or equal to 3 mol %, greater than or equal to 0.5 mol % and less than or equal to 2 mol %, or even greater than or equal to 0.5 mol % and less than or equal to 1 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of MgO.

[0181] In addition to improving Au retention, ZnO lowers the viscosity of the glass compositions, which enhances the formability, the strain point, and the Young's modulus, and may improve ion-exchangeability. However, when too much ZnO is added to the glass composition, the diffusivity of sodium and potassium ions in the glass composition decreases which, in turn, adversely impacts the ion-exchange performance (i.e., the ability to ion-exchange) of the resultant colored glass article.

[0182] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0 mol % and less than or equal to 5 mol % ZnO. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.1 mol % and less than or equal to 4 mol % ZnO. In embodiments, the concentration of ZnO in the glass composition may be greater than or equal to 0 mol %, greater than or equal to 0.1 mol %, greater than or equal to 0.25 mol %, greater than or equal to 0.5 mol %, or even greater than or equal to 0.75 mol %. In embodiments, the concentration of ZnO in the glass composition may be less than or equal to 5 mol %, less than or equal to 4 mol %, less than or equal to 3 mol %, less than or equal to 2.5 mol %, less than or equal to 2 mol %, less than or equal to 1.75 mol %, less than or equal to 1.5 mol %, or even less than or equal to 1.25 mol %. In embodiments, the concentration of ZnO in the glass composition may be greater than or equal to 0 mol % and less than or equal to 5 mol %, greater than or equal to 0 mol % and less than or equal to 4 mol %, greater than or equal to 0 mol % and less than or equal to 3 mol %, greater than or equal to 0 mol % and less than or equal to 2.5 mol %, greater than or equal to 0 mol % and less than or equal to 2 mol %, greater than or equal to 0 mol % and less than or equal to 1.75 mol %, greater than or equal to 0 mol % and less than or equal to 1.5 mol %, greater than or equal to 0 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.1 mol % and less than or equal to 5 mol %, greater than or equal to 0.1 mol % and less than or equal to 4 mol %, greater than or equal to 0.1 mol % and less than or equal to 3 mol %, greater than or equal to 0.1 mol % and less than or equal to 2.5 mol %, greater than or equal to 0.1 mol % and less than or equal to 2 mol %, greater than or equal to 0.1 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.1 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.1 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.25 mol % and less than or equal to 5 mol %, greater than or equal to 0.25 mol % and less than or equal to 4 mol %, greater than or equal to 0.25 mol % and less than or equal to 3 mol %, greater than or equal to 0.25 mol % and less than or equal to 2.5 mol %, greater than or equal to 0.25 mol % and less than or equal to 2 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.5 mol % and less than or equal to 5 mol %, greater than or equal to 0.5 mol % and less than or equal to 4 mol %, greater than or equal to 0.5 mol % and less than or equal to 3 mol %, greater than or equal to 0.5 mol % and less than or equal to 2.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 2 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.75 mol % and less than or equal to 5 mol %, greater than or equal to 0.75 mol % and less than or equal to 4 mol %, greater than or equal to 0.75 mol % and less than or equal to 3 mol %, greater than or equal to 0.75 mol % and less than or equal to 2.5 mol %, greater than or equal to 0.75 mol % and less than or equal to 2 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.5 mol %, or even greater than or equal to 0.75 mol % and less than or equal to 1.25 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of ZnO.

[0183] Like ZnO and the alkaline earth oxide MgO, other alkaline earth oxides, such as CaO, SrO and BaO, decrease the melting point of the glass composition. Accordingly, CaO, SrO, and/or BaO may be included in the glass composition and the resultant colored glass articles to lower the melting point of the glass composition, which may help improve Au retention.

[0184] In embodiments, the concentration of CaO in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol %, greater than or equal to 0.25 mol %, greater than or equal to 0.5 mol %, or even greater than or equal to 0.75 mol %. In embodiments, the concentration of CaO in the glass composition and the resultant colored glass article may be less than or equal to 2 mol %, less than or equal to 1.75 mol %, less than or equal to 1.5 mol %, less than or equal to 1.25 mol %, or even less than or equal to 1 mol %. In embodiments, the concentration of CaO in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol % and less than or equal to 2 mol %, greater than or equal to 0 mol % and less than or equal to 1.75 mol %, greater than or equal to 0 mol % and less than or equal to 1.5 mol %, greater than or equal to 0 mol % and less than or equal to 1.25 mol %, greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0.25 mol % and less than or equal to 2 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.25 mol % and less than or equal to 1 mol %, greater than or equal to 0.5 mol % and less than or equal to 2 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.5 mol % and less than or equal to 1 mol %, greater than or equal to 0.75 mol % and less than or equal to 2 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.25 mol %, or even greater than or equal to 0.75 mol % and less than or equal to 1 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of CaO.

[0185] In embodiments, the concentration of SrO in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol %, greater than or equal to 0.25 mol %, greater than or equal to 0.5 mol %, or even greater than or equal to 0.75 mol %. In embodiments, the concentration of SrO in the glass composition and the resultant colored glass article may be less than or equal to 2 mol %, less than or equal to 1.75 mol %, less than or equal to 1.5 mol %, less than or equal to 1.25 mol %, or even less than or equal to 1 mol %. In embodiments, the concentration of SrO in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol % and less than or equal to 2 mol %, greater than or equal to 0 mol % and less than or equal to 1.75 mol %, greater than or equal to 0 mol % and less than or equal to 1.5 mol %, greater than or equal to 0 mol % and less than or equal to 1.25 mol %, greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0.25 mol % and less than or equal to 2 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.25 mol % and less than or equal to 1 mol %, greater than or equal to 0.5 mol % and less than or equal to 2 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.5 mol % and less than or equal to 1 mol %, greater than or equal to 0.75 mol % and less than or equal to 2 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.25 mol %, or even greater than or equal to 0.75 mol % and less than or equal to 1 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of SrO.

[0186] In embodiments, the concentration of BaO in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol %, greater than or equal to 0.25 mol %, greater than or equal to 0.5 mol %, or even greater than or equal to 0.75 mol %. In embodiments, the concentration of BaO in the glass composition and the resultant colored glass article may be less than or equal to 2 mol %, less than or equal to 1.75 mol %, less than or equal to 1.5 mol %, less than or equal to 1.25 mol %, or even less than or equal to 1 mol %. In embodiments, the concentration of BaO in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol % and less than or equal to 2 mol %, greater than or equal to 0 mol % and less than or equal to 1.75 mol %, greater than or equal to 0 mol % and less than or equal to 1.5 mol %, greater than or equal to 0 mol % and less than or equal to 1.25 mol %, greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0.25 mol % and less than or equal to 2 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.25 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.25 mol % and less than or equal to 1 mol %, greater than or equal to 0.5 mol % and less than or equal to 2 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.5 mol % and less than or equal to 1.25 mol %, greater than or equal to 0.5 mol % and less than or equal to 1 mol %, greater than or equal to 0.75 mol % and less than or equal to 2 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.75 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.75 mol % and less than or equal to 1.25 mol %, or even greater than or equal to 0.75 mol % and less than or equal to 1 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of BaO.

[0187] The glass compositions and the resultant colored glass articles described herein may further comprise ZrO.sub.2. While not wishing to be bound by theory, it is believed that ZrO.sub.2 may act as a multivalent species that serves as redox couples to supply oxygen to Au during relatively low-temperature heat treatment, which helps improve Au retention. ZrO.sub.2 may also act as a colorant in addition to Au, producing colored glass articles that may be, for example, red in color. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.1 mol % and less than or equal to 2 mol % ZrO.sub.2. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.25 mol % and less than or equal to 1.5 mol % ZrO.sub.2. In embodiments, the concentration of ZrO.sub.2 in the glass composition may be greater than or equal to 0 mol %, greater than or equal to 0.1 mol %, or even greater than or equal to 0.2 mol %. In embodiments, the concentration of ZrO.sub.2 in the glass composition may be less than or equal to 2 mol %, less than or equal to 1.5 mol %, less than or equal to 1 mol %, less than or equal to 0.75 mol %, or even less than or equal to 0.5 mol %. In embodiments, the concentration of ZrO.sub.2 in the glass composition may be greater than or equal to 0 mol % and less than or equal to 2 mol %, greater than or equal to 0 mol % and less than or equal to 1.5 mol %, greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0 mol % and less than or equal to 0.75 mol %, greater than or equal to 0 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.1 mol % and less than or equal to 2 mol %, greater than or equal to 0.1 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.1 mol % and less than or equal to 1 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.2 mol % and less than or equal to 2 mol %, greater than or equal to 0.2 mol % and less than or equal to 1.5 mol %, greater than or equal to 0.2 mol % and less than or equal to 1 mol %, greater than or equal to 0.2 mol % and less than or equal to 0.75 mol %, or even greater than or equal to 0.2 mol % and less than or equal to 0.5 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of ZrO.sub.2.

[0188] The glass compositions and the resultant colored glass articles described herein may further comprise Fe.sub.2O.sub.3, which may help improve Au retention. Fe.sub.2O.sub.3 is a multivalent species that may serve as redox couples to supply oxygen to Au during relatively low-temperature heat treatment, which helps improve Au retention. Fe.sub.2O.sub.3 may also act as a colorant in addition to Au, producing colored glass articles that may, for example, be pink in color. In embodiments, the glass composition. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.1 mol % and less than or equal to 1 mol % Fe.sub.2O.sub.3. In embodiments, the concentration of Fe.sub.2O.sub.3 in the glass composition may be greater than or equal to 0 mol % or even greater than or equal to 0.1 mol %. In embodiments, the concentration of Fe.sub.2O.sub.3 in the glass composition may be less than or equal to 1 mol %, less than or equal to 0.75 mol %, or even less than or equal to 0.5 mol %. In embodiments, the concentration of Fe.sub.2O.sub.3 in the glass composition may be greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0 mol % and less than or equal to 0.75 mol %, greater than or equal to 0 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.1 mol % and less than or equal to 1 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.75 mol %, or even greater than or equal to 0.1 mol % and less than or equal to 0.5 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of Fe.sub.2O.sub.3.

[0189] The glass compositions and the resultant colored glass articles described herein may further comprise SnO.sub.2, Sb.sub.2O.sub.3, and/or Bi.sub.2O.sub.3. Like MgO and ZnO, SnO.sub.2, Sb.sub.2O.sub.3, and Bi.sub.2O.sub.3 may help lower the melting point of the glass composition. Accordingly, SnO.sub.2, Sb.sub.2O.sub.3, and/or Bi.sub.2O.sub.3 may be included in the glass composition and the resultant colored glass articles to lower the melting point and improve Au retention.

[0190] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.01 mol % and less than or equal to 1 mol % SnO.sub.2. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.05 mol % and less than or equal to 0.75 mol % SnO.sub.2. In embodiments, the concentration of SnO.sub.2 in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol %, greater than or equal to 0.01 mol %, greater than or equal to 0.05 mol %, or even greater than or equal to 0.1 mol %. In embodiments, the concentration of SnO.sub.2 in the glass composition and the resultant colored glass article may be less than or equal to 1 mol %, less than or equal to 0.75 mol %, less than or equal to 0.5 mol %, or even less than or equal to 0.25 mol %. In embodiments, the concentration of SnO.sub.2 in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0 mol % and less than or equal to 0.75 mol %, greater than or equal to 0 mol % and less than or equal to 0.5 mol %, greater than or equal to 0 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.01 mol % and less than or equal to 1 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.05 mol % and less than or equal to 1 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.1 mol % and less than or equal to 1 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.5 mol %, or even greater than or equal to 0.1 mol % and less than or equal to 0.25 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of SnO.sub.2.

[0191] In embodiments, the concentration of Sb.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol %, greater than or equal to 0.01 mol %, greater than or equal to 0.05 mol %, or even greater than or equal to 0.1 mol %. In embodiments, the concentration of Sb.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be less than or equal to 1 mol %, less than or equal to 0.75 mol %, less than or equal to 0.5 mol %, or even less than or equal to 0.25 mol %. In embodiments, the concentration of Sb.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0 mol % and less than or equal to 0.75 mol %, greater than or equal to 0 mol % and less than or equal to 0.5 mol %, greater than or equal to 0 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.01 mol % and less than or equal to 1 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.05 mol % and less than or equal to 1 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.1 mol % and less than or equal to 1 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.5 mol %, or even greater than or equal to 0.1 mol % and less than or equal to 0.25 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of Sb.sub.2O.sub.3.

[0192] In embodiments, the concentration of Bi.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol %, greater than or equal to 0.01 mol %, greater than or equal to 0.05 mol %, or even greater than or equal to 0.1 mol %. In embodiments, the concentration of Bi.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be less than or equal to 1 mol %, less than or equal to 0.75 mol %, less than or equal to 0.5 mol %, or even less than or equal to 0.25 mol %. In embodiments, the concentration of Bi.sub.2O.sub.3 in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0 mol % and less than or equal to 0.75 mol %, greater than or equal to 0 mol % and less than or equal to 0.5 mol %, greater than or equal to 0 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.01 mol % and less than or equal to 1 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.05 mol % and less than or equal to 1 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.05 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.1 mol % and less than or equal to 1 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.5 mol %, or even greater than or equal to 0.1 mol % and less than or equal to 0.25 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of Bi.sub.2O.sub.3.

[0193] The glass compositions and the resultant colored glass articles described herein may further comprise a reduced concentration or be substantially free or free of P.sub.2O.sub.5. An increased concentration (i.e., greater than 1 mol %) of P.sub.2O.sub.5 may reduce Au retention. While not wishing to be bound by theory, it is believed that P.sub.2O.sub.5 may be more volatile than other glass network formers, such as SiO.sub.2, which may contribute to reduced Au retention. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 0.1 mol % and less than or equal to 1 mol % P.sub.2O.sub.5. In embodiments, the concentration of P.sub.2O.sub.5 in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol %, greater than or equal to 0.1 mol %, greater than or equal to 0.25 mol %, or even greater than or equal to 0.5 mol %. In embodiments, the concentration of P.sub.2O.sub.5 in the glass composition and the resultant colored glass article may be less than or equal to 1 mol % or even less than or equal to 0.75 mol %. In embodiments, the concentration of P.sub.2O.sub.5 in the glass composition and the resultant colored glass article may be greater than or equal to 0 mol % and less than or equal to 1 mol %, greater than or equal to 0 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.1 mol % and less than or equal to 1 mol %, greater than or equal to 0.1 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.25 mol % and less than or equal to 1 mol %, greater than or equal to 0.25 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.5 mol % and less than or equal to 1 mol %, or even greater than or equal to 0.5 mol % and less than or equal to 0.75 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of P.sub.2O.sub.5.

[0194] The glass compositions and the resultant colored glass articles described herein further comprise Au as a colorant to achieve the desired color. As described herein, the glass compositions and the resultant colored glass articles described herein improve the retention of Au, thereby expanding the color gamut achievable by the resultant colored glass articles.

[0195] In embodiments, the glass composition and the resultant colored glass article may comprise greater than 0.0005 mol % and less than or equal to 1 mol % Au. In embodiments, the glass composition and the resultant colored glass article may comprise greater than 0.001 mol % and less than or equal to 0.5 mol % Au. In embodiments, the concentration of Au in the glass composition and the resultant colored glass article may be greater than or equal to 0.0005 mol %, greater than or equal to 0.001 mol %, greater than or equal to 0.002 mol % Au, greater than or equal to 0.005 mol %, or even greater than or equal to 0.01 mol %. In embodiments, the concentration of Au in the glass composition and the resultant colored glass article may be less than or equal to 1 mol %, less than or equal to 0.75 mol %, less than or equal to 0.5 mol %, less than or equal to 0.25 mol %, less than or equal to 0.1 mol %, or even less than or equal to 0.05 mol %. In embodiments, the concentration of Au in the glass composition and the resultant colored glass article may be greater than or equal to 0.0005 mol % and less than or equal to 1 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.1 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.05 mol %, greater than or equal to 0.001 mol % and less than or equal to 1 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.1 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.05 mol %, greater than or equal to 0.002 mol % and less than or equal to 1 mol %, greater than or equal to 0.002 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.002 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.002 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.002 mol % and less than or equal to 0.1 mol %, greater than or equal to 0.002 mol % and less than or equal to 0.05 mol %, greater than or equal to 0.005 mol % and less than or equal to 1 mol %, greater than or equal to 0.005 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.005 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.005 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.005 mol % and less than or equal to 0.1 mol %, greater than or equal to 0.005 mol % and less than or equal to 0.05 mol %, greater than or equal to 0.01 mol % and less than or equal to 1 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.01 mol % and less than or equal to 0.1 mol %, or even greater than or equal to 0.01 mol % and less than or equal to 0.05 mol %, or any and all sub-ranges formed from any of these endpoints.

[0196] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 1×10.sup.−6 mol % and less than or equal to 1 mol % Au. In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.01 mol % Au. In embodiments, the concentration of Au in the glass composition and the resultant colored glass article may be greater than or equal to 1×10.sup.−6 mol %, greater than or equal to 1×10.sup.−5 mol %, greater than or equal to 0.0001 mol %, greater than or equal to 0.0005 mol %, or even greater than or equal to 0.001 mol %. In embodiments, the concentration of Au in the glass composition and the resultant colored glass article may be less than or equal to 1 mol %, less than or equal to 0.75 mol %, less than or equal to 0.5 mol %, less than or equal to 0.25 mol %, less than or equal to 0.1 mol %, less than or equal to 0.05 mol %, or even less than or equal to 0.01. In embodiments, the concentration of Au in the glass composition and the resultant colored glass article may be greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.75 mol %, greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.5 mol %, greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.25 mol %, greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.1 mol %, greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.05 mol %, greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.01 mol %, greater than or equal to 1×10.sup.−5 mol % and less than or equal to 1 mol %, greater than or equal to 1×10.sup.−5 mol % and less than or equal to 0.75 mol %, greater than or equal to 1×10.sup.−5 mol % and less than or equal to 0.5 mol %, greater than or equal to 1×10.sup.−5 mol % and less than or equal to 0.25 mol %, greater than or equal to 1×10.sup.−5 mol % and less than or equal to 0.1 mol %, greater than or equal to 1×10.sup.−5 mol % and less than or equal to 0.05 mol %, greater than or equal to 1×10.sup.−5 mol % and less than or equal to 0.01 mol %, greater than or equal to 0.0001 mol % and less than or equal to 1 mol %, greater than or equal to 0.0001 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.0001 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.0001 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.0001 mol % and less than or equal to 0.1 mol %, greater than or equal to 0.0001 mol % and less than or equal to 0.05 mol %, greater than or equal to 0.0001 mol % and less than or equal to 0.01 mol %, greater than or equal to 0.0005 mol % and less than or equal to 1 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.1 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.05 mol %, greater than or equal to 0.0005 mol % and less than or equal to 0.01 mol %, greater than or equal to 0.001 mol % and less than or equal to 1 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.75 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.5 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.25 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.1 mol %, greater than or equal to 0.001 mol % and less than or equal to 0.05 mol %, or even greater than or equal to 0.001 mol % and less than or equal to 0.01 mol %, or any and all sub-ranges formed from any of these endpoints.

[0197] A different color gamut may be achieved by including other colorants in addition to Au. Accordingly, in embodiments, the glass composition and resultant colored glass article may comprise the glass composition comprises greater than or equal to 0 mol % and less than or equal to 1 mol % of a cation “M”, wherein “M” is at least one of F, Cl, Br, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Se, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Te, W, Ir, Pt, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er.

[0198] In embodiments, the glass compositions and the resultant colored glass articles described herein may further include tramp materials such as TiO.sub.2, MnO, MoO.sub.3, WO.sub.3, Y.sub.2O.sub.3, CdO, As.sub.2O.sub.3, sulfur-based compounds, such as sulfates, halogens, or combinations thereof. In embodiments, the glass composition and the resultant colored glass article may be substantially free or free of tramp materials such as TiO.sub.2, MnO, MoO.sub.3, WO.sub.3, Y.sub.2O.sub.3, CdO, As.sub.2O.sub.3, sulfur-based compounds, such as sulfates, halogens, or combinations thereof. In embodiments, antimicrobial components, chemical fining agents, or other additional components may be included in the glass compositions and the resultant colored glass articles.

[0199] As described herein, decreasing the melting point of the glass composition may help improve Au retention because the glass compositions may be melted at relatively lower temperatures and Au evaporation may be reduced. Accordingly, the glass compositions and the resultant colored glass articles described herein include MgO and/or ZnO, which help lower the melting point of the glass composition. B.sub.2O.sub.3, Li.sub.2O, and Na.sub.2O also decrease the melting point of the glass composition. As described herein, other components may be added to the glass composition to lower the melting point thereof, such as SnO.sub.2, Sb.sub.2O.sub.3, and Bi.sub.2O.sub.3. In embodiments, the glass composition may have a melting point less than or equal to 1550° C. In embodiments, the glass composition may have a melting point greater than or equal to 1300° C., greater than or equal to 1325° C., greater than or equal to 1350° C., greater than or equal to 1375° C., or even greater than or 1400° C. In embodiments, the glass composition may have a melting point less than or equal to 1550° C., less than or equal to 1525° C., less than or equal 1500° C., less than or equal to 1475° C., or even less than or equal to 1450° C. In embodiments, the melting point of the glass composition may be greater than or equal to 1300° C. and less than or equal to 1550° C., greater than or equal to 1300° C. and less than or equal to 1525° C., greater than or equal to 1300° C. and less than or equal to 1500° C., greater than or equal to 1300° C. and less than or equal to 1475° C., greater than or equal to 1300° C. and less than or equal to 1450° C., greater than or equal to 1325° C. and less than or equal to 1550° C., greater than or equal to 1325° C. and less than or equal to 1525° C., greater than or equal to 1325° C. and less than or equal to 1500° C., greater than or equal to 1325° C. and less than or equal to 1475° C., greater than or equal to 1325° C. and less than or equal to 1450° C., greater than or equal to 1350° C. and less than or equal to 1550° C., greater than or equal to 1350° C. and less than or equal to 1525° C., greater than or equal to 1350° C. and less than or equal to 1500° C., greater than or equal to 1350° C. and less than or equal to 1475° C., greater than or equal to 1350° C. and less than or equal to 1450° C., greater than or equal to 1375° C. and less than or equal to 1550° C., greater than or equal to 1375° C. and less than or equal to 1525° C., greater than or equal to 1375° C. and less than or equal to 1500° C., greater than or equal to 1375° C. and less than or equal to 1475° C., greater than or equal to 1375° C. and less than or equal to 1450° C., greater than or equal to 1400° C. and less than or equal to 1550° C., greater than or equal to 1400° C. and less than or equal to 1525° C., greater than or equal to 1400° C. and less than or equal to 1500° C., greater than or equal to 1400° C. and less than or equal to 1475° C., or even greater than or equal to 1400° C. and less than or equal to 1450° C., or any and all sub-ranges formed from any of these endpoints.

[0200] In embodiments, a liquidus temperature of the glass composition may be greater than or equal to 1000° C., greater than or equal to 1050° C., or even greater than or equal to 1100° C. In embodiments, a liquidus temperature of the precursor glass composition may be less than or equal to 1400° C., less than or equal to 1350° C. or even less than or equal to 1300° C. In embodiments, a liquidus temperature of the glass composition may be greater than or equal to 1000° C. and less than or equal to 1400° C., greater than or equal to 1000° C. and less than or equal to 1350° C., greater than or equal to 1000° C. and less than or equal to 1300° C., greater than or equal to 1050° C. and less than or equal to 1400° C., greater than or equal to 1050° C. and less than or equal to 1350° C., greater than or equal to 1000° C. and less than or equal to 1300° C., greater than or equal to 1100° C. and less than or equal to 1400° C., greater than or equal to 1100° C. and less than or equal to 1350° C., or even greater than or equal to 1100° C. and less than or equal to 1300° C., or any and all sub-ranges formed from any of these endpoints.

[0201] In embodiments, the viscosity of the glass composition may be adjusted to prevent devitrification of the glass composition and formation of Au particles before melting. Formation of Au particles before melting may limit the color gamut that may be achieved by heat treatment. Accordingly, in embodiments, to achieve the desired viscosity and thereby prevent formation of Au particles before melting, the glass compositions and the resultant glass articles described herein may satisfy the relationship 5.72*Al.sub.2O.sub.3 (mol %)−21.4*ZnO (mol %)−2.5*P.sub.2O.sub.5 (mol %)−35*Li.sub.2O (mol %)−16.6*B.sub.2O.sub.3 (mol %)−20.5*MgO (mol %)−23.3*Na.sub.2O (mol %)−27.9*SrO (mol %)−18.5*K.sub.2O (mol %)−26.3*CaO (mol %) is greater than −609 mol %. In embodiments, the glass compositions and the resultant glass articles described herein may satisfy the relationship 5.72*Al.sub.2O.sub.3 (mol %)−21.4*ZnO (mol %)−2.5*P.sub.2O.sub.5 (mol %)−35*Li.sub.2O (mol %)−16.6*B.sub.2O.sub.3 (mol %)−20.5*MgO (mol %)−23.3*Na.sub.2O (mol %)−27.9*SrO (mol %)−18.5*K.sub.2O (mol %)−26.3*CaO (mol %) is greater than −609 mol %, greater than or equal to −575 mol %, greater than or equal to −550 mol %, or even greater than or equal to −525 mol %. In embodiments, the glass compositions and the resultant glass articles described herein may satisfy the relationship 5.72*Al.sub.2O.sub.3 (mol %)−21.4*ZnO (mol %)−2.5*P.sub.2O.sub.5 (mol %)−35*Li.sub.2O (mol %)−16.6*B.sub.2O.sub.3 (mol %)−20.5*MgO (mol %)−23.3*Na.sub.2O (mol %)−27.9*SrO (mol %)−18.5*K.sub.2O (mol %)−26.3*CaO (mol %) is less than or equal to −400 mol %, less than or equal to −425 mol %, or even less than or equal to −450 mol %. In embodiments, the glass compositions and the resultant glass articles described herein may satisfy the relationship 5.72*Al.sub.2O.sub.3 (mol %)−21.4*ZnO (mol %)−2.5*P.sub.2O.sub.5 (mol %)−35*Li.sub.2O (mol %)−16.6*B.sub.2O.sub.3 (mol %)−20.5*MgO (mol %)−23.3*Na.sub.2O (mol %)−27.9*SrO (mol %)−18.5*K.sub.2O (mol %)−26.3*CaO (mol %) is greater than −609 mol % and less than or equal to −400 mol %, greater then−609 mol % and less than or equal to −425 mol %, greater than −609 mol % and less than or equal to −450 mol %, greater than or equal to −575 mol % and less than or equal to −400 mol %, greater than or equal to −575 mol % and less than or equal to −425 mol %, greater than or equal to −575 mol % and less than or equal to −450 mol %, greater than or equal to −550 mol % and less than or equal to −400 mol %, greater than or equal to −550 mol % and less than or equal to −425 mol %, greater than or equal to −550 mol % and less than or equal to −450 mol %, greater than or equal to −525 mol % and less than or equal to −400 mol %, greater than or equal to −525 mol % and less than or equal to −425 mol %, or even greater than or equal to −525 mol % and less than or equal to −450 mol %, or any and all sub-ranges formed from any of these endpoints.

[0202] In embodiments, the process for making a glass article includes heat treating a glass composition described herein at one or more preselected temperatures for one or more preselected times to induce glass homogenization. In embodiments, the heat treatment for making a glass article may include (i) heating a glass composition at a rate of 1-100° C./min to glass homogenization temperature; (ii) maintaining the glass composition at the glass homogenization temperature for a time greater than or equal to 0.25 hour and less than or equal to 4 hours to produce a glass article; and (iii) cooling the formed glass article to room temperature. In embodiments, the glass homogenization temperature may be greater than or equal to 300° C. and less than or equal to 700° C.

[0203] The colored glass articles formed from the glass compositions described herein may be any suitable thickness, which may vary depending on the particular application of the colored glass article. In embodiments, the colored glass articles may have a thickness greater than or equal to 250 μm and less than or equal to 6 mm, greater than or equal to 250 μm and less than or equal to 4 mm, greater than or equal to 250 μm and less than or equal to 2 mm, greater than or equal to 250 μm and less than or equal to 1 mm, greater than or equal to 250 μm and less than or equal to 750 μm, greater than or equal to 250 μm and less than or equal to 500 μm, greater than or equal to 500 μm and less than or equal to 6 mm, greater than or equal to 500 μm and less than or equal to 4 mm, greater than or equal to 500 μm and less than or equal to 2 mm, greater than or equal to 500 μm and less than or equal to 1 mm, greater than or equal to 500 μm and less than or equal to 750 μm, greater than or equal to 750 μm and less than or equal to 6 mm, greater than or equal to 750 μm and less than or equal to 4 mm, greater than or equal to 750 μm and less than or equal to 2 mm, greater than or equal to 750 μm and less than or equal to 1 mm, greater than or equal to 1 mm and less than or equal to 6 mm, greater than or equal to 1 mm and less than or equal to 4 mm, greater than or equal to 1 mm and less than or equal to 2 mm, greater than or equal to 2 mm and less than or equal to 6 mm, greater than or equal to 2 mm and less than or equal to 4 mm, or even greater than or equal to 4 mm and less than or equal to 6 mm, or any and all sub-ranges formed from any of these endpoints.

[0204] As discussed hereinabove, colored glass articles formed from the glass compositions described herein may have an increased fracture toughness such that the colored glass articles are more resistant to damage. In embodiments, the colored glass article may have a K.sub.Ic fracture toughness as measured by a double torsion method greater than or equal to 0.7 MPa.Math.m.sup.1/2. In embodiments, the colored glass article may have a K.sub.Ic fracture toughness as measured by a double torsion method greater than or equal to 0.7 MPa.Math.m.sup.1/2, greater than or equal to 0.8 Mpa.Math.m.sup.1/2, greater than or equal to 0.9 MPa.Math.m.sup.1/2, or even greater than or equal to 1.0 Mpa.Math.m.sup.1/2.

[0205] In embodiments, the glass compositions described herein are ion-exchangeable to facilitate strengthening the colored glass article made from the glass compositions. In typical ion-exchange processes, smaller metal ions in the glass compositions are replaced or “exchanged” with larger metal ions of the same valence within a layer that is close to the outer surface of the colored glass article made from the glass composition. The replacement of smaller ions with larger ions creates a compressive stress within the layer of the colored glass article made from the glass composition. In embodiments, the metal ions are monovalent metal ions (e.g., Li.sup.+, Na.sup.+, K.sup.+, and the like), and ion-exchange is accomplished by immersing the glass article made from the glass composition in a bath comprising at least one molten salt of the larger metal ion that is to replace the smaller metal ion in the colored glass article. Alternatively, other monovalent ions such as Ag.sup.+, Tl.sup.+, Cu.sup.+, and the like may be exchanged for monovalent ions. The ion-exchange process or processes that are used to strengthen the colored glass article made from the glass composition may include contacting the colored glass article with an ion-exchange medium. In embodiments, the ion-exchange medium may be a molten salt bath. For example, the ion-exchange process may include, but is not limited to, immersion in a single bath or multiple baths of like or different compositions with optional washing and/or annealing steps between immersions.

[0206] Upon exposure to the colored glass article, the ion-exchange solution (e.g., KNO.sub.3 and/or NaNO.sub.3 molten salt bath) may, according to embodiments, be at a temperature greater than or equal to 350° C. and less than or equal to 500° C., greater than or equal to 360° C. and less than or equal to 450° C., greater than or equal to 370° C. and less than or equal to 440° C., greater than or equal to 360° C. and less than or equal to 420° C., greater than or equal to 370° C. and less than or equal to 400° C., greater than or equal to 375° C. and less than or equal to 475° C., greater than or equal to 400° C. and less than or equal to 500° C., greater than or equal to 410° C. and less than or equal to 490° C., greater than or equal to 420° C. and less than or equal to 480° C., greater than or equal to 430° C. and less than or equal to 470° C., or even greater than or equal to 440° C. and less than or equal to 460° C., or any and all sub-ranges between the foregoing values. In embodiments, the colored glass article may be exposed to the ion-exchange solution for a duration greater than or equal to 2 hours and less than or equal to 24 hours, greater than or equal to 2 hours and less than or equal to 12 hours, greater than or equal to 2 hours and less than or equal to 6 hours, greater than or equal to 8 hours and less than or equal to 24 hours, greater than or equal to 6 hours and less than or equal to 24 hours, greater than or equal to 6 hours and less than or equal to 12 hours, greater than or equal to 8 hours and less than or equal to 24 hours, or even greater than or equal to 8 hours and less than or equal to 12 hours, or any and all sub-ranges formed from any of these endpoints.

[0207] In embodiments, a colored glass article made from a glass composition may be ion-exchanged to achieve a depth of compression of 10 μm or greater, 20 μm or greater, 30 μm or greater, 40 μm or greater, 50 μm or greater, 60 μm or greater, 70 μm or greater, 80 μm or greater, 90 μm or greater, or 100 μm or greater. In embodiments, a colored glass article made from a glass composition may be ion-exchanged to achieve a depth of compression of 3 μm or greater or 5 μm or greater. In embodiments, the colored glass article made from the glass composition may have a thickness “t” and may be ion-exchanged to achieve a depth of compression greater than or equal to 0.15 t, greater than or equal to 0.17 t, or even greater than or equal to 0.2 t. In embodiments, the colored glass article made from the glass composition may have a thickness “t” and may be ion-exchanged to achieve a depth of compression less than or equal to 0.3 t, less than or equal to 0.27 t, or even less than or equal to 0.25 t. In embodiments, the colored glass article made from the glass composition described herein may have a thickness “t” and may be ion-exchanged to achieve a depth of compression greater than or equal to 0.15 t and less than or equal to 0.3 t, greater than or equal to 0.15 t and less than or equal to 0.27 t, greater than or equal to 0.15 t and less than or equal to 0.25 t, greater than or equal to 0.17 t and less than or equal to 0.3 t, greater than or equal to 0.17 t and less than or equal to 0.27 t, greater than or equal to 0.17 t and less than or equal to 0.25 t, greater than or equal to 0.2 t and less than or equal to 0.3 t, greater than or equal to 0.2 t and less than or equal to 0.27 t, or even greater than or equal to 0.2 t and less than or equal to 0.25 t, or any and all sub-ranges formed from any of these endpoints.

[0208] The development of this surface compression layer is beneficial for achieving a better crack resistance and higher flexural strength compared to non-ion-exchanged materials. The surface compression layer has a higher concentration of the ions exchanged into the colored glass article in comparison to the concentration of the ions exchanged into the colored glass article for the body (i.e., the area not including the surface compression) of the colored glass article. In embodiments, the colored glass article made from the glass composition may have a surface compressive stress after ion-exchange strengthening greater than or equal to 300 MPa, greater than or equal to 400 MPa, greater than or equal to 500 MPa, or even greater than or equal to 600 MPa. In embodiments, the colored glass article made from the glass composition may have a surface compressive stress after ion-exchange strengthening less than or equal to 1 GPa, less than or equal to 900 MPa, or even less than or equal to 800 MPa. In embodiments, the colored glass article made from the glass composition may have a surface compressive stress after ion-exchange strengthening greater than or equal to 300 MPa and less than or equal to 1 GPa, greater than or equal to 300 MPa and less than or equal to 900 MPa, greater than or equal to 300 MPa and less than or equal to 800 MPa, greater than or equal to 400 MPa and less than or equal to 1 GPa, greater than or equal to 400 MPa and less than or equal to 900 MPa, greater than or equal to 400 MPa and less than or equal to 800 MPa, greater than or equal to 500 MPa and less than or equal to 1 GPa, greater than or equal to 500 MPa and less than or equal to 900 MPa, greater than or equal to 500 MPa and less than or equal to 800 MPa, greater than or equal to 600 MPa and less than or equal to 1 GPa, greater than or equal to 600 MPa and less than or equal to 900 MPa, greater than or equal to 600 MPa and less than or equal to 800 MPa,

[0209] In embodiments, the colored glass articles made from the glass composition may have a central tension after ion-exchange strengthening greater than or equal to 40 MPa, greater than or equal to 60 MPa, greater than or equal to 80 MPa, or even greater than or equal to 100 MPa. In embodiments, the colored glass article made from the glass composition may have a central tension after ion-exchange strengthening less than or equal to 250 MPa, less than or equal to 200 MPa, or even less than or equal to 150 MPa. In embodiments, the colored glass article made from the glass composition may have a central tension after ion-exchange strengthening greater than or equal to 40 MPa and less than or equal to 250 MPa, greater than or equal to 40 MPa and less than or equal to 200 MPa, greater than or equal to 40 MPa and less than or equal to 150 MPa, greater than or equal to 60 MPa and less than or equal to 250 MPa, greater than or equal to 60 MPa and less than or equal to 200 MPa, greater than or equal to 60 MPa and less than or equal to 150 MPa, greater than or equal to 80 MPa and less than or equal to 250 MPa, greater than or equal to 80 MPa and less than or equal to 200 MPa, greater than or equal to 80 MPa and less than or equal to 150 MPa, greater than or equal to 100 MPa and less than or equal to 250 MPa, greater than or equal to 100 MPa and less than or equal to 200 MPa, or even greater than or equal to 100 MPa and less than or equal to 150 MPa, or any and all sub-ranges formed from any of these endpoints. As utilized herein, central tension refers to a maximum central tension value unless otherwise indicated.

[0210] As described herein, the glass compositions described herein increase the retention of Au, which increases the concentration of Au in the resultant colored glass articles, thereby expanding the color gamut achievable by the colored glass articles. In embodiments, a colored glass article having greater than or equal to 0.01 mol % and less than or equal to 1 mol % Au may have a transmittance color coordinate in the CIELAB color space, as measured at an article thickness of 1.5 mm under F2 illumination and a 10° standard observer angle, of L* greater than or equal to 65 and less than or equal to 97, a* greater than or equal to −5 and less than or equal to 25, and b* greater than or equal to −20 and less than or equal to 5. In embodiments, colored glass article having greater than or equal to 1×10.sup.−6 mol % and less than or equal to 1 mol % Au may have a transmittance color coordinate in the CIELAB color space, as measured at an article thickness of 1.33 mm under F2 illumination and a 10° standard observer angle, of L* greater than or equal to 65 and less than or equal to 98, a* greater than or equal to −10 and less than or equal to 25, and b* greater than or equal to −20 and less than or equal to 5.

[0211] In embodiments, the glass composition and the resultant colored glass article may comprise greater than or equal to 60 mol % and less than or equal to 70 mol % SiO.sub.2; greater than or equal to 11 mol % and less than or equal to 17 mol % Al.sub.2O.sub.3; greater than or equal to 2 mol % and less than or equal to 8 mol % B.sub.2O.sub.3; greater than or equal to 9 mol % and less than or equal to 14 mol % Li.sub.2O; greater than or equal to 2 mol % and less than or equal to 6 mol % Na.sub.2O; greater than or equal to 0.1 mol % and less than or equal to 2 mol % MgO; greater than or equal to 0.1 mol % and less than or equal to 2 mol % ZnO; and greater than or equal to 1×10.sup.−6 mol % and less than or equal to 0.01 mol % Au. In these embodiments, MgO+ZnO is greater than or equal to 0.1 mol % and less than or equal to 4.5 mol %.

[0212] Different color coordinates within the color gamut may be achieved by altering the heat treatment cycle of the glass composition used to produce the resultant colored glass articles. The heat treatment cycle is characterized by the temperature of the environment (i.e., the oven) and the duration of the cycle (i.e., time exposed to the heated environment). As used herein, the phrase “temperature of the heat treatment cycle” refers to the temperature of the environment (i.e., the oven). In embodiments, glass articles formed from the glass compositions described herein are heat treated in an isothermal oven to produce the resultant colored glass articles.

[0213] In embodiments, the temperature of the heat treatment cycle is greater than or equal to 550° C., greater than or equal to 575° C., greater than or equal to 600° C., greater than or equal to 625° C., or even greater than or equal to 650° C. In embodiments, the temperature of the heat treatment cycle is less than or equal to 800° C., less than or equal to 775° C., less than or equal to 750° C., less than or equal to 725° C., or even less than or equal to 700° C. embodiments, the temperature of the heat treatment cycle is greater than or equal to 550° C. and less than or equal to 800° C., greater than or equal to 550° C. and less than or equal to 775° C., greater than or equal to 550° C. and less than or equal to 750° C., greater than or equal to 550° C. and less than or equal to 725° C., greater than or equal to 550° C. and less than or equal to 700° C., greater than or equal to 575° C. and less than or equal to 800° C., greater than or equal to 575° C. and less than or equal to 775° C., greater than or equal to 575° C. and less than or equal to 750° C., greater than or equal to 575° C. and less than or equal to 725° C., greater than or equal to 575° C. and less than or equal to 700° C., greater than or equal to 600° C. and less than or equal to 800° C., greater than or equal to 600° C. and less than or equal to 775° C., greater than or equal to 600° C. and less than or equal to 750° C., greater than or equal to 600° C. and less than or equal to 725° C., greater than or equal to 600° C. and less than or equal to 700° C., greater than or equal to 625° C. and less than or equal to 800° C., greater than or equal to 625° C. and less than or equal to 775° C., greater than or equal to 625° C. and less than or equal to 750° C., greater than or equal to 625° C. and less than or equal to 725° C., greater than or equal to 625° C. and less than or equal to 700° C., greater than or equal to 650° C. and less than or equal to 800° C., greater than or equal to 650° C. and less than or equal to 775° C., greater than or equal to 650° C. and less than or equal to 750° C., greater than or equal to 650° C. and less than or equal to 725° C., or even greater than or equal to 650° C. and less than or equal to 700° C., or any and all sub-ranges formed from any of these endpoints.

[0214] In embodiments, the duration of the heat treatment cycle is greater than or equal to 0.25 hour, greater than or equal to 0.5 hour, greater than or equal 1 hour, or even greater than or equal to 2 hours. In embodiments, the durations of the heat treatment cycle is less than or equal to 24 hours, less than or equal to 16 hours, less than or equal to 8 hours, or even less than or equal to 4 hours. In embodiments, the duration of the heat treatment cycle is greater than or equal to 0.25 hour and less than or equal to 24 hours, greater than or equal to 0.25 hour and less than or equal to 16 hours, greater than or equal to 0.25 hour and less than or equal to 8 hours, greater than or equal to 0.25 hour and less than or equal to 4 hours, greater than or equal to 0.5 hour and less than or equal to 24 hours, greater than or equal to 0.5 hour and less than or equal to 16 hours, greater than or equal to 0.5 hour and less than or equal to 8 hours, greater than or equal to 0.5 hour and less than or equal to 4 hours, greater than or equal to 1 hour and less than or equal to 24 hours, greater than or equal to 1 hour and less than or equal to 16 hours, greater than or equal to 1 hour and less than or equal to 8 hours, greater than or equal to 1 hour and less than or equal to 4 hours, greater than or equal to 2 hours and less than or equal to 24 hours, greater than or equal to 2 hours and less than or equal to 16 hours, greater than or equal to 2 hours and less than or equal to 8 hours, or even greater than or equal to 2 hours and less than or equal to 4 hours, or any and all sub-ranges formed from any of these endpoints.

[0215] In embodiments, the heat treatment may comprise ramping up to a heat treatment temperature at a heating rate and cooling down from the heat treatment temperature at a cooling rate. In embodiments, the selected heating rate and cooling down rate may effect the color coordinates of the resultant colored glass articles.

[0216] In embodiments, the heating rate of the heat treatment may be greater than or equal to 2° C./min or even greater than or equal to 3° C./min. In embodiments, the heating rate of the heat treatment may be less than equal to 10° C./min, less than or equal to 7° C./min, or even less than or equal to 5° C./min. In embodiments, the heating rate of the heat treatment may be greater than or equal to 2° C./min and less than or equal to 10° C./min, greater than or equal to 2° C./min and less than or equal to 7° C./min, greater than or equal to 2° C./min and less than or equal to 5° C./min, greater than or equal to 3° C./min and less than or equal to 10° C./min, greater than or equal to 3° C./min and less than or equal to 7° C./min, or even greater than or equal to 3° C./min and less than or equal to 5° C./min, or any and all sub-ranges formed from any of these endpoints.

[0217] In embodiments, the cooling rate of the heat treatment may be greater than or equal to 1° C./min or even greater than or equal to 2° C./min. In embodiments, the cooling rate of the heat treatment may be less than or equal to 10° C./min, less than or equal to 8° C./min, less than or equal to 6° C./min, or even less than or equal to 4° C./min. In embodiments, the cooling rate of the heat treatment may be greater than or equal to 1° C./min and less than or equal to 10° C./min, greater than or equal to 1° C./min and less than or equal to 8° C./min, greater than or equal to 1° C./min and less than or equal to 6° C./min, greater than or equal to 1° C./min and less than or equal to 4° C./min, greater than or equal to 2° C./min and less than or equal to 10° C./min, greater than or equal to 2° C./min and less than or equal to 8° C./min, greater than or equal to 2° C./min and less than or equal to 6° C./min, or even greater than or equal to 2° C./min and less than or equal to 4° C./min, or any and all sub-ranges formed from any of these endpoints.

[0218] In embodiments, the glass compositions are heat treated in an isothermal oven to produce the resultant colored glass articles.

[0219] The colored glass articles described herein may be used for a variety of applications including, for example, back cover applications in consumer or commercial electronic devices such as smartphones, tablet computers, personal computers, ultrabooks, televisions, and cameras. An exemplary article incorporating any of the colored glass articles disclosed herein is shown in FIGS. 1 and 2. Specifically, FIGS. 1 and 2 show a consumer electronic device 100 including a housing 102 having front 104, back 106, and side surfaces 108; electrical components (not shown) that are at least partially inside or entirely within the housing and including at least a controller, a memory, and a display 110 at or adjacent to the front surface of the housing; and a cover substrate 112 at or over the front surface of the housing such that it is over the display. In embodiments, at least a portion of housing 102, such as the back 106, may include any of the colored glass articles disclosed herein.

EXAMPLES

[0220] In order that various embodiments be more readily understood, reference is made to the following examples, which illustrate various embodiments of the colored glass articles described herein.

[0221] Heat Treatment—The heat treatment of the Examples below included placing the glass articles between a SiC setter, heating to the indicated heat treatment temperature at a rate of 4° C./min, and cooling from the heat treatment temperature after the heat treatment time had lapsed at a cooling rate of 3° C./min.

[0222] Table 1 shows comparative examples C1 and C2 and examples 1-30, with the batch compositions utilized to form each example reported (in terms of mol %). Table 1 also reports the heat treatment used to produce colored glass articles from the batch compositions and the analyzed Au concentration (in terms of mol %) of the resultant colored glass articles.

TABLE-US-00001 TABLE 1 Example 1 2 3 C1 C2 4 SiO.sub.2 58.8 58.8 58.8 58.5 58.5 58.5 Al.sub.2O.sub.3 16.5 16.5 16.5 16.5 16.5 16.5 B.sub.2O.sub.3 6.0 6.0 6.0 6.0 6.0 6.0 Li.sub.2O 10.0 10.0 10.0 12.0 12.0 10.0 Na.sub.2O 4.5 4.5 4.5 6.5 6.5 4.5 K.sub.2O 0.2 0.2 0.2 0.5 0.5 0.5 MgO 3.0 3.0 3.0 — — 3.0 ZnO 1.0 1.0 1.0 — — 1.0 ZrO.sub.2 — — — — — — P.sub.2O.sub.5 — — — — — — SnO.sub.2 — — — — — — Fe.sub.2O.sub.3 — — — — — — Au 0.005 0.005 0.005 0.010 0.020 0.010 R.sub.2O 14.7 14.7 14.7 19.0 19.0 15.0 MgO + ZnO 4.0 4.0 4.0 0.0 0.0 4.0 R.sub.2O − Al.sub.2O.sub.3 1.8 −1.8 −1.8 2.5 2.5 −1.5 5.72*Al2O3 − −546.7 −546.7 −546.7 −585.9 −585.9 −552.2 21.4*ZnO − 2.5*P2O5 − 35*Li2O − 16.6*B2O3 − 20.5*MgO − 23.3*Na2O − 27.9*SrO − 18.5*K2O − 26.3*CaO HEAT TREATMENT Melting temperature 1550 1500 1450 1450 1450 1450 (° C.) Melting time (hours) 18 18 18 18 18 18 Analyzed Au (mol %) 0.0009 0.0017 0.0018 0.0013 0.0023 0.0030 % of Au retained 18.0 34.0 36.0 13.0 11.5 30.0 Example 5 6 7 8 9 10 SiO.sub.2 58.5 60.7 60.7 60.7 60.7 60.7 Al.sub.2O.sub.3 16.5 14.5 14.5 14.5 14.5 14.5 B.sub.2O.sub.3 6.0 6.0 6.0 6.0 6.0 6.0 Li.sub.2O 10.0 10.0 10.0 10.0 10.0 10.0 Na.sub.2O 4.5 4.5 4.5 4.5 4.5 4.5 K.sub.2O 0.5 0.5 0.5 0.5 0.5 0.2 MgO 3.0 3.0 3.0 3.0 3.0 3.0 ZnO 1.0 1.0 1.0 1.0 1.0 1.0 ZrO.sub.2 — — 0.5 — 0.5 0.5 P.sub.2O.sub.5 — — — 1.0 1.0 — SnO.sub.2 — 0.10 0.10 0.10 0.10 0.05 Fe.sub.2O.sub.3 — — — — — — Au 0.020 0.005 0.005 0.005 0.005 0.005 R.sub.2O 15.0 15.0 15.0 15.0 15.0 14.7 MgO + ZnO 4.0 4.0 4.0 4.0 4.0 4.0 R.sub.2O − Al.sub.2O.sub.3 −1.5 0.5 0.5 0.5 0.5 0.2 5.72*Al.sub.2O.sub.3 − −552.2 −563.7 −563.7 −566.2 −566.2 −558.1 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO HEAT TREATMENT Melting temperature 1450 1550 1550 1550 1550 1550 (° C.) Melting time (hours) 18 18 18 18 18 18 Analyzed Au (mol %) 0.0043 0.0013 0.0018 0.0006 0.0007 0.0019 % of Au retained 21.5 26.0 36.0 12.0 14.0 38.0 Example 11 12 13 14 15 16 SiO.sub.2 60.7 60.7 60.7 61.8 61.8 61.8 Al.sub.2O.sub.3 14.5 14.5 14.5 14.5 14.5 14.5 B.sub.2O.sub.3 6.0 6.0 6.0 6.0 6.0 6.0 Li.sub.2O 10.0 10.0 10.0 6.5 6.5 6.5 Na.sub.2O 4.5 4.5 4.5 8.0 8.0 8.0 K.sub.2O 0.2 0.2 0.2 0.2 0.2 0.2 MgO 3.0 3.0 3.0 2.0 2.0 2.0 ZnO 1.0 1.0 1.0 1.0 1.0 1.0 ZrO.sub.2 0.2 0.3 0.5 — — 0.2 P.sub.2O.sub.5 — — — — — — SnO.sub.2 0.01 0.03 0.05 — 0.05 0.05 Fe.sub.2O.sub.3 — — — — — — Au 0.005 0.005 0.005 0.005 0.005 0.005 R.sub.2O 14.7 14.7 14.7 14.7 14.7 14.7 MgO + ZnO 4.0 4.0 4.0 3.0 3.0 3.0 R.sub.2O − Al.sub.2O.sub.3 0.2 0.2 0.2 0.2 0.2 0.2 5.72*Al.sub.2O.sub.3 − −558.1 −558.1 −558.1 −496.7 −496.7 −496.7 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO HEAT TREATMENT Melting temperature 1550 1550 1550 1500 1500 1500 (° C.) Melting time (hours) 18 18 18 18 18 18 Analyzed Au (mol %) 0.0013 0.0016 0.0017 0.0009 0.0010 0.0012 % of Au retained 26.0 32.0 34.0 18.0% 20.0% 24.0% Example 17 18 19 20 21 22 SiO.sub.2 61.8 61.8 61.8 60.8 60.8 60.8 Al.sub.2O.sub.3 14.5 14.5 14.5 15.5 15.5 15.5 B.sub.2O.sub.3 6.0 6.0 6.0 6.0 6.0 6.0 Li.sub.2O 6.5 6.5 6.5 6.5 6.5 6.5 Na.sub.2O 8.0 8.0 8.0 8.0 8.0 8.0 K.sub.2O 0.2 0.2 0.2 0.2 0.2 0.2 MgO 2.0 2.0 2.0 2.0 2.0 2.0 ZnO 1.0 1.0 1.0 1.0 1.0 1.0 ZrO.sub.2 — — 0.2 — — 0.2 P.sub.2O.sub.5 — — — — — — SnO.sub.2 — 0.05 0.05 — 0.05 0.05 Fe.sub.2O.sub.3 — — — — — — Au 0.005 0.005 0.005 0.005 0.005 0.005 R.sub.2O 14.7 14.7 14.7 14.7 14.7 14.7 MgO + ZnO 3.0 3.0 3.0 3.0 3.0 3.0 R.sub.2O − Al.sub.2O.sub.3 0.2 0.2 0.2 −0.8 −0.8 −0.8 5.72*Al.sub.2O.sub.3 − −496.7 −496.7 −496.7 −490.9 −490.9 −490.9 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO HEAT TREATMENT Melting temperature 1500 1500 1500 1500 1500 1500 (° C.) Melting time (hours) 18 18 18 18 18 18 Analyzed Au (mol %) 0.0010 0.0011 0.0014 0.0012 0.0012 0.0012 % of Au retained 20.0% 22.0% 28.0% 24.0% 24.0% 24.0% Example 23 24 25 26 27 28 SiO.sub.2 61.2 61.2 60.7 60.7 60.7 60.7 Al.sub.2O.sub.3 14.5 14.5 14.5 14.5 14.5 14.5 B.sub.2O.sub.3 6.0 6.0 6.0 6.0 6.0 6.0 Li.sub.2O 6.5 6.5 8.0 9.0 9.0 9.0 Na.sub.2O 8.0 8.0 4.5 4.5 4.5 4.5 K.sub.2O 0.8 0.8 0.2 0.2 0.2 0.2 MgO 2.0 2.0 4.0 4.0 3.0 4.0 ZnO 1.0 1.0 2.0 1.0 2.0 1.0 ZrO.sub.2 — — — — — — P.sub.2O.sub.5 — — — — — — SnO.sub.2 0.10 0.10 0.05 0.05 0.05 0.05 Fe.sub.2O.sub.3 0.05 0.05 0.10 0.05 0.05 0.10 Au 0.005 0.005 0.005 0.005 0.005 0.005 R.sub.2O 15.3 15.3 12.7 13.7 13.7 13.7 MgO + ZnO 3.0 3.0 6.0 5.0 5.0 5.0 R.sub.2O − Al.sub.2O.sub.3 0.8 0.8 −1.8 −0.8 −0.8 −0.8 5.72*Al.sub.2O.sub.3 − −506.8 −506.8 −530.0 −543.6 −544.5 −543.6 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO HEAT TREATMENT Melting temperature 1500 1500 1500 1500 1500 1500 (° C.) Melting time (hours) 16 16 18 18 18 18 Analyzed Au (mol %) 0.0016 0.0017 0.0005 0.0009 0.0005 0.0006 % of Au retained 32.0% 34.0% 10.0% 18.0% 10.0% 12.0% Example 29 30 SiO.sub.2 61.2 61.2 Al.sub.2O.sub.3 14.5 14.5 B.sub.2O.sub.3 6.0 6.0 Li.sub.2O 6.5 6.5 Na.sub.2O 8.0 8.0 K.sub.2O 0.8 0.8 MgO 2.0 2.0 ZnO 1.0 1.0 ZrO.sub.2 — — P.sub.2O.sub.5 — — SnO.sub.2 0.10 0.10 Fe.sub.2O.sub.3 0.05 0.05 Au 0.005 0.005 R.sub.2O 15.3 15.3 MgO + ZnO 3.0 3.0 R.sub.2O − Al.sub.2O.sub.3 −0.8 −0.8 5.72*Al.sub.2O.sub.3 − −544.5 −544.5 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO HEAT TREATMENT Melting temperature 1500 1500 (° C.) Melting time (hours) 18 18 Analyzed Au (mol %) 0.0006 0.0013 % of Au retained 12.0% 26.0%

[0223] Referring to Table 1, Examples 1-3 were formed from the same glass composition, but melted at different temperatures. Example 1, which was melted at 1550° C., had an Au retention of 18.0%. Examples 2 and 3, which were melted at 1500° C. and 1450° C., respectively, had Au retentions of 34.0% and 36.0%, respectively. As indicated by Examples 1-3, a lower melting temperature favors Au retention. Therefore, it may be desirable to form a glass composition having a lower melting point such that Au retention during processing may be improved.

[0224] Comparative Examples C1 and C2 had an Au retention of 13.0% and 11.5%, respectively, after being melted at 1450° C. for 18 hours. Examples 4 and 5, which were similar to Comparative Examples C1 and C2, respectively, but included MgO and ZnO, had Au retentions of 30.0% and 21.5%, respectively, after being melted at 1450° C. for 18 hours. As indicated by Comparative Examples C1 and C2 and Examples 4 and 5, including MgO and ZnO in the glass composition improves Au retention of the resultant colored glass article.

[0225] Example 6 had an Au retention of 26.0% after being melted at 1550° C. for 18 hours. Example 7, which was similar to Example 3 but included ZrO.sub.2, had an Au retention of 36.0% after being melted at 1550° C. for 18 hours. As indicated by Examples 6 and 7, including ZrO.sub.2 in addition to MgO and ZnO in the glass composition improves Au retention of the resultant colored glass article.

[0226] Examples 8 and 9, which were similar to Examples 6 and 7, respectively, but included P.sub.2O.sub.5, had lower Au retentions of 12.0% and 14.0%, respectively, after being melted at 1550° C. for 18 hours. As indicated by Examples 6-9, including P.sub.2O.sub.5 in the glass composition impairs Au retention of the resultant colored glass article.

[0227] Examples 10-13, which included ZrO.sub.2 and SnO.sub.2, had relatively higher Au retentions of 38.0%, 26.0%, 32.0%, and 34%, respectively, after being melted at 1550° C. for 18 hours. As indicated by Examples 10-13, including SnO.sub.2 in addition to MgO, ZnO, and ZrO.sub.2 in the glass compositions improves Au retention of the resultant colored glass article.

[0228] Examples 14 and 17 had an Au retention of 18.0% and 20.0%, respectively, after being melted at 1550° C. for 18 hours. Examples 15 and 18, which were similar to Examples 14 and 17, but included SnO.sub.2, had an Au retention of 20.0% and 22%, respectively, after being melted at 1550° C. for 18 hours. As indicated by Examples 15 and 18, including SnO.sub.2 in addition to MgO and ZnO in the glass composition improves Au retention of the resultant colored glass article.

[0229] Examples 16 and 19, which included ZrO.sub.2 and SnO.sub.2, had relatively higher Au retentions of 24.0% and 28.0%, respectively, after being melted at 1550° C. for 18 hours. As indicated by Examples 16 and 19, including SnO.sub.2 in addition to MgO, ZnO, and ZrO.sub.2 in the glass compositions improves Au retention of the resultant colored glass article.

[0230] Examples 23 and 24, which included Fe.sub.2O.sub.3, had relatively higher Au retentions of 32.0% and 34.0%, respectively, after being melted at 1550° C. for 18 hours. As indicated by Examples 23 and 24, including Fe.sub.2O.sub.3 in addition to MgO, ZnO, and ZrO.sub.2 in the glass compositions improves Au retention of the resultant colored glass article.

[0231] Referring now to FIGS. 3A-3C, 4A-4C, 5A-5C, and 6A-6C, a gradient-temperature approach was used to identify the heat treatment cycle parameters (i.e., temperature and duration) to achieve the desired color coordinates. Specifically, a 12 cm long and 1.5 mm thick sample formed from the glass composition of Example 11 was placed in a gradient-temperature oven and held at a heat treatment temperature, which varied along the length of the sample, for the prescribed duration. The sample was then rapidly cooled to quench the sample and the precipitated Au particles therein. Optical transmission spectra were then measured every 2 mm along the direction of the gradient. The coordinates in the CIELAB color space were plotted, as measured under F2 illumination and a 10° standard observer angle, in which the heat treatment temperature moved through the color space with separate plots for the four different heat treatment durations: 0.25 hour (FIGS. 3A-3C), 0.5 hour (FIGS. 4A-4C), 1 hour (FIGS. 5A-5C), and 1.5 hour (FIGS. 6A-6C). As indicated by FIGS. 3A-3C, 4A-4C, 5A-5C, and 6A-6C, different heat treatment temperatures and durations may be used to achieve the desired color.

[0232] Note that, as described herein, processing of the glass compositions to produce the resultant colored glass articles may occur in an isothermal oven. However, a gradient-temperature oven was used in these examples to investigate a range of temperatures simultaneously. A gradient-temperature oven produces similar results as an isothermal oven at the desired temperature.

[0233] Table 2 shows examples 31-65, with the analyzed concentration (in terms of mol %) of the resultant colored glass articles.

TABLE-US-00002 TABLE 2 Example 31 32 33 34 35 36 SiO.sub.2 61.09 61.03 61.08 60.99 60.87 60.73 Al.sub.2O.sub.3 14.51 14.50 14.51 14.49 14.44 14.58 B.sub.2O.sub.3 6.00 6.00 5.86 5.93 5.91 5.94 Li.sub.2O 9.94 9.94 10.07 10.10 10.01 10.10 Na.sub.2O 4.30 4.33 4.28 4.28 4.25 4.31 K.sub.2O 0.19 0.19 0.19 0.19 0.45 0.19 MgO 2.89 2.90 2.89 2.89 2.89 2.93 ZnO 1.00 1.00 0.99 0.99 0.99 1.05 ZrO.sub.2 0.22 0.30 0.45 0.50 0.03 0.00 P.sub.2O.sub.5 — — — — — — SnO.sub.2 0.02 0.03 0.05 0.07 0.11 0.11 Fe.sub.2O.sub.3 0.02 0.02 0.02 0.02 0.02 0.00 Au 0.0013 0.0015 0.0017 0.0019 0.0013 0.0009 R.sub.2O 14.43 14.46 14.54 14.57 14.71 14.60 MgO + ZnO 3.89 3.90 3.88 3.88 3.88 3.98 R.sub.2O − Al.sub.2O.sub.3 −0.08 −0.04 0.03 0.08 0.27 0.02 5.72*Al.sub.2O.sub.3 − −548.9 −549.8 −550.4 −552.7 −553.6 −555.2 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO Example 37 38 39 40 41 42 SiO.sub.2 61.26 60.71 59.87 60.15 59.28 61.36 Al.sub.2O.sub.3 14.38 14.65 14.86 15.43 15.07 15.72 B.sub.2O.sub.3 5.89 5.95 5.95 5.88 5.70 6.00 Li.sub.2O 10.00 10.05 10.14 10.01 9.80 10.21 Na.sub.2O 4.28 4.30 4.31 4.27 6.03 4.34 K.sub.2O 0.19 0.19 0.19 0.19 0.18 0.20 MgO 2.86 2.93 3.11 2.89 2.80 0.97 ZnO 1.01 1.06 1.09 1.02 0.99 1.05 ZrO.sub.2 0.00 0.00 0.32 0.00 0.00 0.00 P.sub.2O.sub.5 — — — — — — SnO.sub.2 0.06 0.05 0.05 0.11 0.10 0.11 Fe.sub.2O.sub.3 0.00 0.07 0.07 0.00 0.00 0.00 Au 0.0007 0.0005 0.0007 0.0008 0.0005 0.0010 R.sub.2O 14.47 14.54 14.64 14.47 16.01 14.75 MgO + ZnO 3.87 3.99 4.20 3.91 3.79 2.02 R.sub.2O − Al.sub.2O.sub.3 0.09 −0.11 −0.22 −0.96 0.94 −0.97 5.72*Al.sub.2O.sub.3 − −549.0 −553.2 −559.7 −543.8 −573.8 −514.2 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO Example 43 44 45 46 47 48 SiO.sub.2 60.94 59.36 60.40 60.59 60.56 60.64 Al.sub.2O.sub.3 16.51 16.42 15.52 15.32 15.23 15.08 B.sub.2O.sub.3 5.89 5.78 6.05 6.04 6.04 6.01 Li.sub.2O 10.05 9.90 10.66 10.65 10.63 10.74 Na.sub.2O 4.27 4.22 4.77 4.79 4.89 4.90 K.sub.2O 0.19 0.19 0.19 0.19 0.20 0.20 MgO 0.97 2.94 0.97 0.97 0.98 0.97 ZnO 1.03 1.03 1.02 1.02 1.05 1.05 ZrO.sub.2 0.00 0.00 0.31 0.32 0.31 0.32 P.sub.2O.sub.5 — — — — — — SnO.sub.2 0.10 0.11 0.05 0.06 0.06 0.05 Fe.sub.2O.sub.3 — — — — — — Au 0.0010 0.0006 0.0008 0.0008 0.0008 0.0007 R.sub.2O 14.51 14.31 15.62 15.63 15.72 15.84 MgO + ZnO 2.00 3.97 1.99 1.99 2.03 2.02 R.sub.2O − Al.sub.2O.sub.3 −2.00 −2.11 0.10 0.31 0.49 0.76 5.72*Al.sub.2O.sub.3 − −500.0 −532.7 −541.1 −542.2 −545.4 −549.6 21.4*ZnO− 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16 6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO Example 49 50 51 52 53 54 SiO.sub.2 60.94 59.36 60.40 60.59 62.14 62.08 Al.sub.2O.sub.3 16.51 16.42 15.52 15.32 14.95 14.98 B.sub.2O.sub.3 5.89 5.78 6.05 6.04 6.06 5.93 Li.sub.2O 10.05 9.90 10.66 10.65 10.51 10.69 Na.sub.2O 4.27 4.22 4.77 4.79 4.29 4.31 K.sub.2O 0.19 0.19 0.19 0.19 0.14 0.14 MgO 0.97 2.94 0.97 0.97 0.50 0.50 ZnO 1.03 1.03 1.02 1.02 1.03 1.00 ZrO.sub.2 0.00 0.00 0.31 0.32 0.29 0.29 P.sub.2O.sub.5 — — — — — — SnO.sub.2 0.10 0.11 0.05 0.06 0.04 0.04 Fe.sub.2O.sub.3 — — — — 0.04 0.04 Au 0.0008 0.0010 0.0012 0.0015 0.0014 0.0011 R.sub.2O 14.51 14.31 15.62 15.63 14.94 15.14 MgO + ZnO 2.00 3.97 1.99 1.99 1.54 1.51 R.sub.2O − Al.sub.2O.sub.3 −2.00 −2.11 0.10 0.31 −0.01 0.16 5.72*Al.sub.2O.sub.3 − −556.1 −558.4 −557.7 −558.9 −517.8 −521.6 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO Example 55 56 57 58 59 60 SiO.sub.2 62.06 61.95 61.95 61.67 61.01 60.66 Al.sub.2O.sub.3 14.92 14.87 14.88 14.88 14.96 15.03 B.sub.2O.sub.3 5.92 5.91 5.92 5.93 6.04 6.06 Li.sub.2O 10.86 11.03 11.04 11.06 11.18 11.21 Na.sub.2O 4.25 4.24 4.24 4.25 4.26 4.28 K.sub.2O 0.14 0.14 0.14 0.14 0.14 0.14 MgO 0.50 0.50 0.49 0.50 0.50 0.50 ZnO 1.01 1.02 1.01 1.02 1.03 1.03 ZrO.sub.2 0.28 0.28 0.28 0.28 0.28 0.28 P.sub.2O.sub.5 — — — 0.21 0.56 0.76 SnO.sub.2 0.04 0.04 0.04 0.04 0.04 0.04 Fe.sub.2O.sub.3 0.02 0.01 — — — — Au 0.0010 0.0010 0.0011 0.0010 0.0010 0.0010 R.sub.2O 15.25 15.41 15.42 15.46 15.58 15.63 MgO + ZnO 1.51 1.52 1.50 1.52 1.53 1.54 R.sub.2O − Al.sub.2O.sub.3 0.33 0.54 0.55 0.58 0.62 0.60 5.72*Al.sub.2O.sub.3 − −526.5 −532.6 −532.8 −534.9 −541.5 −543.7 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO Example 61 62 63 64 65 SiO.sub.2 60.51 60.49 60.80 60.94 61.47 Al.sub.2O.sub.3 15.06 15.02 14.76 14.61 14.60 B.sub.2O.sub.3 6.06 6.07 6.05 5.97 5.91 Li.sub.2O 11.21 11.22 11.20 11.17 11.12 Na.sub.2O 4.30 4.30 4.29 4.29 4.27 K.sub.2O 0.14 0.14 0.14 0.15 0.15 MgO 0.51 0.51 0.51 0.51 0.50 ZnO 1.03 1.04 1.03 1.03 1.04 ZrO.sub.2 0.28 0.28 0.28 0.48 0.50 P.sub.2O.sub.5 0.86 0.89 0.90 0.81 0.40 SnO.sub.2 0.04 0.04 0.04 0.04 0.04 Fe.sub.2O.sub.3 — — — — — Au 0.0009 0.0010 0.0009 0.0011 0.0010 R.sub.2O 15.65 15.67 15.63 15.61 15.53 MgO + ZnO 1.54 1.54 1.53 1.54 1.54 R.sub.2O − Al.sub.2O.sub.3 0.59 0.65 0.87 1.00 0.93 5.72*Al.sub.2O.sub.3 − −544.2 −545.2 −545.1 −543.6 −539.3 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16 6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO

[0234] Referring now to Table 3, example glass articles 31-35 having the concentrations shown in Table 2 were subjected to isothermal heat treatment between 600° C. and 660° C. The observable colors of the resultant colored glass articles are shown in Table 3. Heat treating glass articles E31, E32, and E33 having an analyzed R.sub.2O—Al.sub.2O.sub.3 of −0.08 mol %, −0.04 mol %, and 0.03 mol %, respectively, resulted in observably pink, purple, and red colored glass articles. Heat treating glass articles E34 and E35, having an analyzed R.sub.2O—Al.sub.2O.sub.3 of 0.08 mol % and 0.27 mol %, respectively, resulted in observably red and orange colored glass articles. As indicated by Tables 2 and 3, the analyzed R.sub.2O—Al.sub.2O.sub.3 of a glass article may be adjusted and the glass article may be subjected to a certain heat treatment to provide a desired colored glass article.

TABLE-US-00003 TABLE 3 Example 31 32 33 34 35 Observable pink, pink, pink, pink, orange, colors purple purple purple red, red purple

[0235] Referring now to Table 4, example glass articles 36-48 having the analyzed concentrations shown in Table 2 were subjected to heat treatment at the temperature and for the period of time shown in Table 4. The observable colors of the resultant colored glass articles are shown in Table 4.

TABLE-US-00004 TABLE 4 550° 575° 600° 625° 650° Heat C. for C. for C. for C. for C. for treatment 2 hrs. 2 hrs. 2 hrs. 2 hrs. 2 hrs. 36 purple purple purple purple — 37 clear, purple purple red — purple 38 pink pink pink pink — 39 red red red red — 40 clear, purple purple purple — purple 41 orange orange orange orange — 42 clear, purple purple purple — purple 43 clear clear purple purple — 44 clear clear purple purple — 45 purple purple purple red red 46 clear, purple purple red red purple 47 purple purple red red red 48 purple purple red red red

[0236] Example glass article E41, having an analyzed R.sub.2O—Al.sub.2O.sub.3 of 0.94 mol %, was the only glass article to result in an observably orange colored glass article after heat treatment. Example glass articles E36-E40 and E42-E48 had an R.sub.2O—Al.sub.2O.sub.3 of 0.76 mol % or less. Heat treating glass article E38, including Fe.sub.2O.sub.3, resulted in an observably pink colored glass article. Heat treating glass articles E39 and E45-48, including ZrO.sub.2, resulted in red colored glass articles. As indicated by Tables 2 and 4, the analyzed R.sub.2O—Al.sub.2O.sub.3 may be adjusted, additional components may be added to the glass composition, and the glass article may be subjected to a certain heat treatment to provide a desired colored glass article.

[0237] Table 5 shows examples 66-75, with the analyzed concentration (in terms of mol %) of the resultant colored glass articles.

TABLE-US-00005 TABLE 5 Example 66 67 68 69 70 71 SiO.sub.2 62.15 62.27 62.22 62.19 62.08 61.95 Al.sub.2O.sub.3 14.93 14.97 14.90 14.95 14.98 14.87 B.sub.2O.sub.3 6.09 5.98 6.03 6.03 5.93 5.91 Li.sub.2O 10.50 10.45 10.53 10.50 10.69 11.03 Na.sub.2O 4.30 4.30 4.28 4.27 4.31 4.24 K.sub.2O 0.14 0.14 0.14 0.14 0.14 0.14 MgO 0.50 0.50 0.50 0.50 0.50 0.50 ZnO 1.03 1.00 1.03 1.04 1.00 1.02 ZrO.sub.2 0.28 0.29 0.28 0.29 0.29 0.28 P.sub.2O.sub.5 0.00 0.00 0.00 0.00 0.00 0.00 SnO.sub.2 0.04 0.04 0.04 0.04 0.04 0.04 Fe.sub.2O.sub.3 0.04 0.04 0.04 0.04 0.04 0.01 Au 6.0 × 10−6 9.0 × 10−6 1.2 × 10−5 1.1 × 10−5 8.0 × 10−6 1.0 × 10−5 R.sub.2O 14.94 14.89 14.95 14.91 15.14 15.41 MgO + ZnO 1.53 1.50 1.53 1.54 1.50 1.52 R.sub.2O − Al.sub.2O.sub.3 0.01 −0.08 0.05 −0.04 0.16 0.54 5.72*Al.sub.2O.sub.3 − −518.27 −513.82 −518.03 −516.67 −521.57 −532.56 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO Example 72 73 74 75 SiO.sub.2 61.67 61.47 62.75 61.67 Al.sub.2O.sub.3 14.88 14.60 14.47 14.88 B.sub.2O.sub.3 5.93 5.91 5.88 5.93 Li.sub.2O 11.06 11.12 11.07 11.06 Na.sub.2O 4.25 4.27 4.27 4.25 K.sub.2O 0.14 0.15 0.15 0.14 MgO 0.50 0.50 0.29 0.50 ZnO 1.02 1.04 0.47 1.02 ZrO.sub.2 0.28 0.50 0.52 0.28 P.sub.2O.sub.5 0.21 0.40 0.08 0.21 SnO.sub.2 0.04 0.04 0.04 0.04 Fe.sub.2O.sub.3 0.00 0.00 0.00 0.00 Au 8.3 × 10−6 8.3 × 10−6 8.3 × 10−6 8.3 × 10−6 R.sub.2O 15.45 15.54 15.49 15.45 MgO + ZnO 1.52 1.54 0.76 1.52 R.sub.2O − Al.sub.2O.sub.3 0.57 0.94 1.02 0.57 5.72*Al.sub.2O.sub.3 − −534.64 −539.57 −520.76 −534.64 21.4*ZnO − 2.5*P.sub.2O.sub.5 − 35*Li.sub.2O − 16.6*B.sub.2O.sub.3 − 20.5*MgO − 23.3*Na.sub.2O − 27.9*SrO − 18.5*K.sub.2O − 26.3*CaO

[0238] Referring now to Table 6, example glass articles 66 and 68-75 having the analyzed concentrations shown in Table 5 were subjected to heat treatment at the temperature and for the period of time shown in Table 6. The observable colors of the resultant colored glass articles are shown in Table 6.

TABLE-US-00006 TABLE 6 Heat 550° C. for 575° C. for 600° C. for 625° C. for 650° C. for 550° C. for 575° C. for treatment 2 hrs. 2 hrs. 2 hrs. 2 hrs. 2 hrs. 8 hrs. 8 hrs. 66 — blue blue blue — — — 68 — blue blue red — — — 69 — purple purple red — — — 70 red purple blue blue — — — 71 clear, blue blue purple — — — purple — — — 72 clear, purple purple purple — — — purple — — — 73 clear, purple purple purple — — — purple 74 clear, purple purple red red red red purple 75 — — purple red red purple red

[0239] Example glass articles 71-75, having an analyzed R.sub.2O—Al.sub.2O.sub.3 of greater than or equal to 0.54 mol %, had a relatively limited achievable color gamut after being subjected to different heat treatments. As indicated by Table 6, a relatively increased R.sub.2O—Al.sub.2O.sub.3 may limit the achievable color gamut of the colored glass article.

[0240] Referring now to Table 7, example glass article 66 having the analyzed concentrations shown in Table 5 and the thicknesses shown in Table 7 were subjected to heat treatment at the temperature and for the period of time shown in Table 7. The transmittance color coordinate in the CIELAB color space, as measured at the indicated article thickness under F2 illumination and a 10° standard observer angle, and the observable color of the resultant colored glass articles are shown in Table 7.

TABLE-US-00007 TABLE 7 525° C. for 535° C. for 535° C. for 545° C. for 575° C. for Thickness 6 hrs. 6 hrs. 10 hrs. 10 hrs. 2 hrs. L* 96.39 95.09 92.01 91.06 92.75 a* 0.15 1.68 4.21 2.53 −0.60 b* 0.27 −0.12 −2.12 −3.64 −2.62 Observable color clear pink pink purple blue 1.33 mm L* 96.14 94.18 86.80 84.96 87.95 a* 0.31 2.60 8.81 3.50 −1.67 b* 0.42 −0.09 −4.55 −7.99 −5.86 Observable color clear pink pink purple blue 2.06 mm L* 95.69 90.65 83.19 78.95 83.25 a* 0.55 6.37 13.52 6.58 −3.01 b* 0.63 −0.97 −4.53 −11.46 −8.40 Observable color clear pink pink purple blue 600° C. for 625° C. for Thickness 2 hrs. 2 hrs.  0.6 mm L* 93.60 92.21 a* −0.61 −0.12 b* −0.60 −1.91 Observable color blue blue 1.33 mm L* 90.23 87.41 a* −1.34 −0.15 b* −1.72 −4.02 Observable color blue blue 2.06 mm L* 86.49 82.29 a* −2.05 −0.24 b* −2.30 −5.93 Observable color blue blue

[0241] Referring now to Table 8, example glass article 68 having the analyzed concentrations shown in Table 5 and the thicknesses shown in Table 8 were subjected to heat treatment at the temperature and for the period of time shown in Table 8. The transmittance color coordinate in the CIELAB color space, as measured at the indicated article thickness under F2 illumination and a 10° standard observer angle, and the observable color of the resultant colored glass articles are shown in Table 8.

TABLE-US-00008 TABLE 8 545° C. for 550° C. for 555° C. for 535° C. for 545° C. for Thickness 2 hrs. 2 hrs. 1.5 hrs. 10 hrs. 4 hrs.  0.6 mm L* 93.11 92.14 91.56 91.16 90.79 a* 3.74 4.82 4.74 6.02 5.90 b* −0.62 −1.31 −2.06 −0.27 −1.33 Observable color pink pink pink red pink 1.33 mm L* 89.09 87.26 86.79 85.12 84.78 a* 7.98 9.84 9.46 12.00 11.74 b* −1.42 −2.58 −3.64 −0.72 −2.32 Observable color pink purple pink red pink 2.06 mm L* 84.41 81.51 81.40 79.52 78.50 a* 12.63 15.29 14.09 17.14 17.21 b* −2.25 −4.01 −5.39 −0.26 −3.16 Observable color pink purple pink red red 560° C. for 555° C. for 570° C. for 625° C. for 600° C. for Thickness 0.75 hrs. 4 hrs. 0.75 hrs. 3 hrs. 2 hrs.  0.6 mm L* 92.14 89.13 88.96 88.74 89.18 a* 4.61 5.00 4.90 2.75 −1.05 b*-1.57 −1.57 −3.95 −4.51 −4.49 −4.32 Observable color pink purple purple purple purple 1.33 mm L* 85.56 81.32 79.76 80.41 79.58 10.56 10.79 7.38 5.66 −2.04 b* −4.34 −7.51 −10.45 −9.10 −9.85 Observable color pink purple purple purple purple 2.06 mm L* 77.01 74.55 70.91 71.91 71.33 a* 16.22 16.05 8.60 8.16 −2.76 b* −8.50 −9.19 −15.68 −13.36 −14.14 Observable color pink pinke purple purple purple 575° C. for 575° C. for Thickness 2 hrs. 4 hrs.  0.6 mm L* 88.09 88.92 −01.8 1.77 b* −5.64 −4.80 Observable color blue blue 1.33 mm L* 78.27 80.57 0.17 3.42 b* −11.89 −9.88 Observable color blue blue 2.06 mm L* 70.17 72.06 a* −0.58 4.74 b* −16.48 −14.79 Observable color blue blue

[0242] Referring now to Table 9, example glass article 68 having the analyzed concentrations shown in Table 5 and the thicknesses shown in Table 9 were subjected to heat treatment at the temperature and for the period of time shown in Table 9. The transmittance color coordinate in the CIELAB color space, as measured at the indicated article thickness under F2 illumination and a 10° standard observer angle, and the observable color of the resultant colored glass articles are shown in Table 9.

TABLE-US-00009 TABLE 9 530° C. for 535° C. for 545° C. for 550° C. for 555° C. for Thickness 3 hrs. 6 hrs. 2 hrs. 2 hrs. 1.5 hrs.  0.6 mm L* 94.72 90.50 89.99 88.79 88.58 1.96 6.78 7.30 7.58 7.50 b* 0.34 0.18 −0.85 −1.80 −2.57 Observable color pink pink pink pink pink 1.33 mm L* 92.64 84.15 83.50 80.52 79.57 3.99 13.49 14.01 14.51 14.41 b* 0.62 0.67 −0.95 −3.71 −5.60 Observable color pink red red pink pink 2.06 mm L* 90.49 77.92 74.81 72.37 71.79 a* 6.07 19.65 21.74 20.56 21.07 b* 0.97 1.59 −1.98 −5.27 −6.54 Observable color pink red pink pink pink 555° C. for 650° C. for 540° C. for 565° C. for 585° C. for Thickness 4 hrs. 2 hrs. 3 hrs. 1.75 hrs. 2 hrs.  0.6 mm L* 88.59 87.25 88.03 86.62 87.36 6.20 7.01 4.98 3.98 2.37 b* −2.50 −4.14 −4.41 −5.65 −5.52 Observable color purple purple purple purple purple 1.33 mm L* 80.63 77.89 78.78 76.92 77.59 13.13 13.81 10.10 8.92 5.17 b* −3.71 −7.35 −8.78 −10.22 −10.98 Observable color purple purple purple purple purple 2.06 mm L* 71.87 68.47 70.21 67.15 68.17 a* 18.44 19.71 14.96 12.94 7.47 b* −6.46 −10.62 −12.00 −14.54 −15.73 Observable color purple purple purple purple purple 560° C. for 600° C. for Thickness 0.75 hrs. 2 hrs.  0.6 mm L* 87.04 87.56 0.99 1.39 b* −6.09 −5.32 Observable color blue blue 1.33 mm L* 77.03 77.57 3.32 2.56 b* −11.99 −10.84 Observable color blue blue 2.06 mm L* 67.17 68.30 a* 3.12 4.07 b* −17.38 −15.38 Observable color blue blue

[0243] As indicated in Tables 7-9, colored glass articles including Au may be subjected to different heat treatment to achieve a desired observable color.

[0244] Table 10 shows the surface compressive stress CS, depth of layer DOLL, and maximum central tension CT of example glass article 67 after being subjected to heat treatment at 545° C. for 2 hrs. and then being subjected to ion-exchange under the conditions listed in Table 10.

TABLE-US-00010 Table 10 IOX temp. (° C.) 400 400 400 400 400 400 400 IOX time (hrs.) 5 6 7 8 6 6.5 6.5 KNO.sub.3 in 83.0 83.0 83.0 83.0 83.0 83.0 80.0 IOX bath (wt %) NaNO.sub.3 in 15.4 15.4 15.4 15.4 15.6 15.0 18.0 IOX bath (wt %) LiNO.sub.3 in 1.6 1.6 1.6 1.6 1.4 2.0 2.0 IOX bath (wt %) CS (MPa) 720 643 632 623 657 621 611 DOC (μm) 4.46 4.86 5.36 5.44 5.00 5.04 4.85 CT (MPa) 111.1 117.4 116.3 115.6 119.2 109.1 118.2

[0245] It will be apparent to those skilled in the art that various modifications and variations may be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.