Patent Publication Number: US-2023143241-A1

Title: Tinted aluminosilicate glass compositions and glass articles including same

Description:
This is a continuation of U.S. patent application Ser. No. 16/098,690 filed on Nov. 2, 2018, which claims the benefit of International Application No. PCT/US2017/030953, filed on May 4, 2017, which claims the benefit of priority of U.S. Provisional Application Serial No. application claims the benefit of priority to U.S. Application No. 62/331,803, filed on May 4, 2016, the content of each of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Field 
     This disclosure relates to tinted aluminosilicate glass compositions and glass articles including the same, and more particularly, to alkali-free aluminosilicate glass compositions that include copper as a tinting agent. 
     Technical Background 
     A variety of different materials can be added to a glass sheet to impart a desired tint or color to the glass sheet. However, glasses of certain colors are difficult to manufacture and/or require costly tinting agents. For example, forming red glass often requires the use of costly tinting agents, such as Au, Ag, or Nd, or the use of toxic tinting agents, such as U, CdS, CdSe, or Se. In addition, tinted glasses are generally formed of an alkali glass material, which may not be compatible with some applications, such as electronics applications. Accordingly, there is a need for alkali-free glass compositions that include inexpensive and safe tinting agents. 
     SUMMARY 
     According to various embodiments, provided are alkali-free aluminosilicate glass compositions comprising copper as a tinting agent, and glass articles comprising the glass composition. The glass articles may be sheets of the glass composition, or may be laminated glass articles that include a glass core layer and one or more glass cladding layers fused to the glass core layer. At least one of the glass core layer or the glass cladding layer or layers of the laminated glass articles comprises the glass composition. 
     According to various embodiments, provided are tinted glass compositions comprising: on an oxide basis: about 45 mol % to about 80 mol % SiO 2 ; about 6 mol % to about 22 mol % Al 2 O 3 ; 0 mol % to about 25 mol % B 2 O 3 ; about 7 mol % to about 25 mol % of at least one alkaline earth oxide selected from the group consisting of MgO, CaO, SrO, BaO, and combinations thereof, about 0.5 mol % to about 20 mol % CuO; 0 mol % to about 6 mol % SnO 2 , SnO, or a combination thereof; 0 mol % to about 1 mol % C; 0 mol % to about 5 mol % La 2 O 3 ; and 0 mol % to about 10 mol % PbO, and that is free or substantially free of alkali metal. 
     Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional view of an exemplary glass article, according to various embodiments of the present disclosure. 
         FIG.  2    is a cross-sectional view of one exemplary embodiment of an overflow distributor that can be used to form an exemplary glass article, according to various embodiments of the present disclosure. 
         FIGS.  3 - 5    are graphs showing the transmittance spectra of different exemplary glass compositions, according to various embodiments of the present disclosure. 
         FIG.  6    is a graph showing color coordinates for blue, green and colorless glasses. 
         FIG.  7    is a graph showing color coordinates for red glasses. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to exemplary embodiments which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. The components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the exemplary embodiments. 
     As used herein, the term “average coefficient of thermal expansion” refers to the average coefficient of linear thermal expansion of a given material or layer between 0° C. and 300° C. As used herein, the term “coefficient of thermal expansion” refers to the average coefficient of thermal expansion unless otherwise indicated. The CTE can be determined, for example, using the procedure described in ASTM E228 “Standard Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilatometer” or ISO 7991:1987 “Glass—Determination of coefficient of mean linear thermal expansion.” 
     Herein, glass compositions are expressed in terms of mol % amounts of particular components included therein on an oxide bases unless otherwise indicated. Any component having more than one oxidation state may be present in a glass composition in any oxidation state. However, concentrations of such component are expressed in terms of the oxide in which such component is at its lowest oxidation state unless otherwise indicated. Component amounts may be provided as ranges, and end points of different ranges for a given component may be combined to define an amount range for the given component. Herein, elements having more than one oxidation state may be present in a glass composition in any oxidation state thereof. 
     In various embodiments, a glass article comprises at least a first layer and a second layer. For example, the first layer comprises a core layer, and the second layer comprises one or more cladding layers adjacent to the core layer. The core layer and the cladding layer may be relative terms. At least one layer of the glass article comprises a tinted layer. The tinted layer comprises one or more tinting agents configured to impart a tint or color to the tinted layer. The first layer and/or the second layer may be glass layers comprising a glass, a glass-ceramic, or a combination thereof. In some embodiments, the first layer and/or the second layer may be transparent glass layers. For example, the first layer and/or the second layer comprises an average transmittance of at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 98%, or at least about 99% over a wavelength range of about 400 nm to about 750 nm. In some embodiments, the first layer and/or the second layer comprise opal glass that may be translucent or opaque. The glass article can comprise a glass sheet or a shaped glass article comprising a suitable 3-dimensional (3D) shape. In some embodiments, an average coefficient of thermal expansion (CTE) of the first layer is greater than an average CTE of the second layer. Such a CTE mismatch can aid in strengthening the glass article. 
       FIG.  1    is a cross-sectional view of an exemplary embodiment of a laminate glass article  100  that comprises laminated glass layers. The glass article  100  can be planar or substantially planar as shown in  FIG.  1   , or may be non-planar. For example, the glass article  100  may be molded or shaped. The glass article  100  comprises a first layer and a second layer. In the embodiment shown in  FIG.  1   , the first layer comprises a core layer  102 , and the second layer comprises a first cladding layer  104  and a second cladding layer  106 . The core layer  102  is disposed between the first cladding layer  104  and the second cladding layer  106 . In some embodiments, the first cladding layer  104  and the second cladding layer  106  may be exterior layers, as shown in  FIG.  1   . In other embodiments, the first cladding layer  104  and/or the second cladding layer  106  may be intermediate layers disposed between the core layer  102  and an exterior layer. 
     The core layer  102  comprises a first major surface and a second major surface opposite the first major surface. In some embodiments, the first cladding layer  104  is fused to the first major surface of the core layer  102 . Additionally, or alternatively, the second cladding layer  106  is fused to the second major surface of the core layer  102 . In such embodiments, the interfaces between the first cladding layer  104  and the core layer  102  and/or between the second cladding layer  106  and the core layer  102  may be free of any bonding material such as, for example, a polymer interlayer, an adhesive, a coating layer, or any non-glass material added or configured to adhere the respective cladding layers to the core layer. Thus, the first cladding layer  104  and/or the second cladding layer  106  may be fused directly to the core layer  102 , or may be directly adjacent to core layer  102 . 
     In various exemplary embodiments, the glass article  100  may comprise one or more intermediate layers disposed between the core layer  102  and the first cladding layer  104 , and/or between the core layer  102  and the second cladding layer  106 . For example, the intermediate layers comprise intermediate glass layers and/or diffusion layers formed at the interface of the core layer  102  and the cladding layers  104 ,  106 . The diffusion layer can comprise a blended region comprising components of each layer adjacent to the diffusion layer. Thus, two directly adjacent glass layers may be fused at the diffusion layer. In some embodiments, glass article  100  comprises a glass-glass laminate (e.g., an in-situ fused multilayer glass-glass laminate) in which the interfaces between directly adjacent glass layers are glass-glass interfaces. 
     In some embodiments, the core layer  102  comprises a first glass composition, and the first and/or second cladding layers  104 ,  106  comprise a second glass composition that is different than the first glass composition. For example, in the embodiment shown in  FIG.  1   , the core layer  102  comprises the first glass composition, and each of the first and second cladding layers  104 ,  106  comprises the second glass composition. In other embodiments, the first cladding layer  104  comprises the second glass composition, and the second cladding layer  106  comprises a third glass composition that is different than the first glass composition and/or the second glass composition. 
     The glass article  100  can be formed using a suitable process such as, for example, a fusion draw, down draw, slot draw, up draw, or float process. The various layers of the glass article can be laminated during forming of the glass article  100  or formed independently and subsequently laminated to form the glass article  100 . In some embodiments, the glass article is formed using a fusion draw process. 
       FIG.  2    is a cross-sectional view of one exemplary embodiment of an overflow distributor  200  that can be used to form a glass article such as, for example, glass article  100 . The overflow distributor  200  can be configured as described in U.S. Pat. No. 4,214,886, which is incorporated herein by reference in its entirety. For example, overflow distributor  200  comprises a lower overflow distributor  220  and an upper overflow distributor  240  positioned above the lower overflow distributor. Lower overflow distributor  220  comprises a trough  222 . A first glass composition  224  is melted and fed into the trough  222  in a viscous state. The first glass composition  224  forms core layer  102  of the glass article  100  as further described below. The upper overflow distributor  240  comprises a trough  242 . A second glass composition  244  is melted and fed into the trough  242  in a viscous state. The second glass composition  244  forms first and second cladding layers  104  and  106  of glass article  100  as further described below. 
     The first glass composition  224  overflows trough  222  and flows down opposing outer forming surfaces  226  and  228  of the lower overflow distributor  220 . The outer forming surfaces  226  and  228  converge at a draw line  230 . The separate streams of first glass composition  224  flowing down respective outer forming surfaces  226  and  228  of the lower overflow distributor  220  converge at the draw line  230 , where they are fused together to form the core layer  102  of the glass article  100 . 
     The second glass composition  244  overflows the trough  242  and flows down opposing outer forming surfaces  246  and  248  of the upper overflow distributor  240 . The second glass composition  244  is deflected outward by the upper overflow distributor  240 , such that the second glass composition flows around the lower overflow distributor  220  and contacts the first glass composition  224  flowing over the outer forming surfaces  226  and  228  of the lower overflow distributor  220 . The separate streams of the second glass composition  244  are fused to the respective separate streams of the first glass composition  224  flowing down respective outer forming surfaces  226  and  228  of the lower overflow distributor  220 . Upon convergence of the streams of first glass composition  224  at draw line  230 , the second glass composition  244  forms the first and second cladding layers  104  and  106  of the glass article  100 . 
     In some embodiments, the first glass composition  224  of core layer  102  in the viscous state is contacted with the second glass composition  244  of the first and second cladding layers  104 ,  106  in the viscous state to form the laminated sheet. In some of such embodiments, the laminated sheet is part of a glass ribbon traveling away from the draw line  230  of the lower overflow distributor  220 , as shown in  FIG.  2   . The glass ribbon can be drawn away from the lower overflow distributor  220  by, for example, gravity and/or pulling rollers. The glass ribbon cools as it travels away from the lower overflow distributor  220 . The glass ribbon is severed to for the glass article  100  using a suitable technique, such as, for example, scoring, bending, thermally shocking, and/or laser cutting. 
     Although glass article  100  shown in  FIG.  1    comprises three layers, other embodiments are intended to be included in this disclosure. In other embodiments, a glass article can have a determined number of layers, such as two, four, or more layers. For example, a glass article comprising two layers can be formed using two overflow distributors positioned so that the two layers are joined while traveling away from the respective draw lines of the overflow distributors or using a single overflow distributor with a divided trough so that two glass compositions flow over opposing outer forming surfaces of the overflow distributor and converge at the draw line of the overflow distributor. A glass article comprising four or more layers can be formed using additional overflow distributors and/or using overflow distributors with divided troughs. Thus, a glass article having a determined number of layers can be formed by modifying the overflow distributor accordingly. 
     In some embodiments, at least one of the core layer  102 , first cladding layer  104 , or the second cladding layer  106  comprises a tinted glass composition. For example, a first glass composition may comprise a tinting agent such that core layer  102  comprises a tinted layer. Additionally, or alternatively, a second glass composition may comprise a tinting agent such that first cladding layer  104  and/or second cladding layer  106  comprises a tinted layer. 
     In further embodiments, the first cladding layer and the second cladding layer may comprise different glass compositions as described herein. In some of such embodiments, one or both of a second glass composition or a third glass composition may comprise a tinting agent such that the corresponding first cladding layer and/or second cladding layer comprise a tinted layer. For example, the first cladding layer and the second cladding layer can comprise the same or a different tinting agent such that the first cladding layer and the second cladding layer have the same or a different tint or color. 
     In some embodiments, more than one layer of the glass article  100  comprises a tinted glass material. For example, the core layer  102  and at least one of the first cladding layer  104  or the second cladding layer  106  may comprise a tinted glass material. In some of such embodiments, the color of the core layer  102  and the color of the cladding layer  104  and/or the cladding layer  106  may be different from each other. Thus, the core layer  102  comprises a different tint or color than first cladding layer  104  and/or second cladding layer  106 . In such embodiments, the glass article  100  comprises a tint or color that is a combination of the tint or color of core layer  102  and the different tint or color of first cladding layer  104  and/or second cladding layer  106 . Thus, different tinted glass materials of different layers of the glass article  100  can be used to give the glass article  100  an overall desired tint or color. 
     In some embodiments, at least one layer of the glass article  100  includes a glass material that comprises copper as a tinting agent. However, in other embodiments, one or more other layers of the glass article  100  may include a glass material that comprises a different tinting agent, such as a transition metal selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Au, Ag, Pt, Ni, Mo, and, W, rare earth elements, and combinations thereof. 
     In some embodiments, the glass composition of one layer may be better suited to incorporate the tinting agent than the glass composition of another layer. Thus, in at least certain embodiments, the laminate structure of the glass article enables the tinting agent that will yield the desired color to be incorporated into the layer with the glass composition with which the tinting agent is most compatible. 
     In some embodiments, the glass article  100  comprises a thickness of at least about 0.05 mm, at least about 0.1 mm, at least about 0.2 mm, or at least about 0.3 mm. Additionally, or alternatively, glass article  100  comprises a thickness of at most about 5 mm, at most about 3 mm, at most about 2 mm, at most about 1.5 mm, at most about 1 mm, at most about 0.7 mm, or at most about 0.5 mm. By way of non-limiting example only, the glass article  100  may comprise a thickness of from about 0.2 mm to about 3 mm, from about 1 mm to about 3 mm, or from about 1.5 mm to about 2.5 mm. In some embodiments, a ratio of a thickness of the core layer  102  to a thickness of the glass article  100  is at least about 0.7, at least about 0.8, at least about 0.85, at least about 0.9, or at least about 0.95. In some embodiments, a thickness of the second layer (e.g., each of the first cladding layer  104  and the second cladding layer  106 ) is from about 0.01 mm to about 0.3 mm. 
     In some embodiments, the cladding layer is thinner than the core layer. For example, each of the first cladding layer and the second cladding layer is thinner than the core layer disposed therebetween as described herein. In some of such embodiments, the first cladding layer and/or the second cladding layer comprise a tinting agent such that the respective cladding layer comprises the tinted layer. Confining the tinting agent to the relatively thin cladding layers can reduce the amount of tinting agent used to achieve the desired tint or color in the glass article. Additionally, or alternatively, a smaller glass melting apparatus (e.g., melting tank) can be used to form the glass material with the tinting agent for the relatively thin cladding layers, compared to the melting apparatus used to form the glass material of the core layer. Thus, a relatively smaller batch of glass material comprising the tinting agent can be used, and the time required to switch to a different glass material (e.g., comprising a different tinting agent) can be reduced. 
     In some embodiments, the first glass composition and/or the second glass composition comprise a liquidus viscosity suitable for forming glass article  100  using a fusion draw process as described herein. For example, the first glass composition of the first layer (e.g., core layer  102 ) comprises a liquidus viscosity of at least about 100 kP, at least about 200 kP, or at least about 300 kP. Additionally, or alternatively, the first glass composition comprises a liquidus viscosity of at most about 3000 kP, at most about 2500 kP, at most about 1000 kP, or at most about 800 kP. 
     Additionally, or alternatively, the second glass composition of the second layer (e.g., first and/or second cladding layers  104  and  106 ) comprises a liquidus viscosity of at least about 50 kP, at least about 100 kP, or at least about 200 kP. Additionally, or alternatively, the second glass composition comprises a liquidus viscosity of at most about 3000 kP, at most about 2500 kP, at most about 1000 kP, or at most about 800 kP. The first glass composition can aid in carrying the second glass composition over the overflow distributor to form the second layer. Thus, the second glass composition can comprise a liquidus viscosity that is lower than generally considered suitable for forming a single layer sheet using a fusion draw process. 
     In some embodiments, the liquidus viscosity of one layer/glass composition may be better suited to incorporate the tinting agent that the liquidus viscosity of another layer/glass composition. Thus, the laminate structure of the glass article enables the tinting agent that will yield the desired color to be incorporated into a layer having a liquidus viscosity with which the tinting agent is most compatible. 
     In some embodiments, glass article  100  may be configured as a strengthened glass article. For example, in some embodiments, the second glass composition of the first and/or second cladding layers  104 ,  106  comprises a different average coefficient of thermal expansion (CTE) than the first glass composition of the core layer  102 . For example, the first and second cladding layers  104 ,  106  may be formed from a glass composition having a lower average CTE than the core layer  102 . The CTE mismatch (i.e., the difference between the average CTE of first and/or second cladding layers  104  and  106  and the average CTE of core layer  102 ) results in formation of compressive stress in the cladding layers and tensile stress in the core layer upon cooling of glass article  100 . Such strengthening can be achieved without subjecting the glass article  100  to a thermal strengthening (e.g., tempering) or chemical strengthening (e.g., ion exchange) process. Thus, strengthening the glass article  100  by CTE mismatch as described herein can enable the use of tinting agents that are incompatible with thermal strengthening and/or chemical strengthening processes, for example, copper doped glasses, which tend to be incompatible with chemical strengthening processes because such process can extract copper ions from the glass. In various embodiments, each of the first and/or second cladding layers, independently, can have a higher average CTE, a lower average CTE, or substantially the same average CTE as the core layer. 
     In some embodiments, the average CTE of the core layer  102  and the average CTE of the first and/or second cladding layers  104 ,  106  differ by at least about 5×10 −7 ° C. −1 , at least about 15×10 −7 ° C. −1 , at least about 25×10 −7 ° C. −1 , or at least about 30×10 −7 ° C. −1 . Additionally, or alternatively, the average CTE of the core layer  102  and the average CTE of the first and/or second cladding layers  104 ,  106  differ by at most about 100×10 −7 ° C. −1 , at most about 75×10 −7 ° C. −1  at most about 50×10 −7 ° C. −1 , at most about 40×10 −7 ° C. −1 , at most about 30×10 −7 ° C. −1 , at most about 20×10 −7 ° C. −1 , or at most about 10×10 −7 ° C. −1 . In some embodiments, the second glass composition of first and/or second cladding layers  104  and  106  comprises an average CTE of at most about 66×10 −7 ° C. −1 , at most about 55×10 −7 ° C. −1 , at most about 50×10 −7 ° C. −1 , at most about 40×10 −7 ° C. −1 , or at most about 35×10 −7 ° C. −1 . Additionally, or alternatively, the second glass composition of first and/or second cladding layers  104  and  106  comprises an average CTE of at least about 25×10 −7 ° C. −1 , or at least about 30×10 −7 ° C. −1 . Additionally, or alternatively, the first glass composition of core layer  102  comprises an average CTE of at least about 40×10 −7 ° C. −1 , at least about 50×10 −7 ° C. −1 , at least about 55×10 −7 ° C. −1 , at least about 65×10 −7 ° C. −1 , at least about 70×10 −7 ° C. −1 , at least about 80×10 −7 ° C. −1 , or at least about 90×10 −7 ° C. −1 . Additionally, or alternatively, the first glass composition of core layer  102  comprises an average CTE of at most about 110×10 −7 ° C. −1 , at most about 100×10 −7 ° C. −1 , at most about 90×10 −7 ° C. −1 , at most about 75×10 −7 ° C. −1 , or at most about 70×10 −7 ° C. −1 . 
     In some embodiments, one or more layers of the glass article  100  comprise an ion exchangeable glass composition. For example, the first cladding layer  104  and/or the second cladding layer  106  comprise an ion exchangeable glass composition such that the glass article can be further strengthened (e.g., to achieve a surface compressive stress greater than that achieved by CTE mismatch) after formation thereof. Exemplary ion exchangeable glass compositions suitable for use in the cladding layers include, but are not limited to, those described in U.S. Patent Application Pub. No. 2015/0030827, which is incorporated herein by reference in its entirety. For example, in some embodiments, the first cladding layer and/or the second cladding layer comprises an alkali metal. 
     The core layer  102  can comprise an alkali metal or can be substantially free (e.g., can comprise less than about 0.1 mol %) or free of alkali metal. Additionally, or alternatively, core layer  102  may comprise an ion exchangeable glass composition such that the glass article can be further strengthened (e.g., to achieve an increased compressive stress at the core/clad interface by ion exchange between adjacent layers of the glass article and/or to achieve a surface compressive stress at an exposed portion of the core layer along an edge of the glass article) after formation thereof. Exemplary ion exchangeable glass compositions suitable for use in the core layer include, but are not limited to, Corning® Gorilla® Glass compositions. The cladding layer can comprise an alkali metal or can be substantially free (e.g., comprise less than about 0.1 mol %) or free of alkali metal. 
     In some embodiments, the tint or color generated by the tinting agent can be affected by subjecting the glass article to an ion exchange process. For example, in embodiments in which the first cladding layer  104  and/or the second cladding layer  106  comprise the tinting agent, the glass article  100  can be subjected to an ion exchange process to generate the desired color (e.g., by changing the behavior of the tinting agent present in the cladding layer). Additionally, or alternatively, the core layer  102  comprises the tinting agent such that the glass article  100  can be subjected to the ion exchange process (e.g., to further strengthen the first cladding layer  104  and/or second the cladding layer  106 ) without substantially changing the tint or color generated by the tinting agent. Thus, the cladding layers protect the core layer during the ion exchange process so that the tinting agent is not substantially affected by the ion exchange process. 
     In various embodiments, the relative thicknesses of the glass layers can be selected to achieve a glass article having desired strength properties. For example, in some embodiments, the first glass composition of the core layer  102  and the second glass composition of the first and/or second cladding layers  104 ,  106  are selected to achieve a desired CTE mismatch, and the relative thicknesses of the glass layers are selected, in combination with the desired CTE mismatch, to achieve a desired compressive stress in the cladding layers and tensile stress in the core layer. Without wishing to be bound by any theory, it is believed that the strength of the glass article can be determined predominantly by the relative thicknesses of the glass layers and the compressive stress in the cladding layers, and that the breakage pattern of the glass article can be determined predominantly by the relative thicknesses of the glass layers and the tensile stress in the core layer. Thus, the glass compositions and relative thicknesses of the glass layers can be selected to achieve a glass article having a desired strength and/or breakage pattern. 
     The glass article can have the desired strength and/or breakage pattern in an as-formed condition without additional processing (e.g., thermal tempering or ion-exchange treatment). For example, the as-formed glass sheet or shaped glass article can have an improved strength as compared to thermally tempered or ion-exchanged glass articles as described herein. 
     In some embodiments, the compressive stress of the cladding layers is at most about 800 MPa, at most about 500 MPa, at most about 350 MPa, or at most about 150 MPa. Additionally, or alternatively, the compressive stress of the cladding layers is at least about 10 MPa, at least about 20 MPa, at least about 30 MPa, at least about 50 MPa, or at least about 250 MPa. Additionally, or alternatively, the tensile stress of the core layer is at most about 150 MPa, or at most about 100 MPa. Additionally, or alternatively, the tensile stress of the core layer is at least about 5 MPa, at least about 10 MPa, at least about 25 MPa, or at least about 50 MPa. 
     In some embodiments, glass article  100  is configured as a durable glass article. For example, glass article  100  is resistant to degradation in response to exposure to a reagent. In some embodiments, the second glass composition of the first and/or second cladding layers  104 ,  106  comprises a durable glass composition that is resistant to degradation in response to exposure to the reagent. In some embodiments, the glass article comprises a core covered with a cladding. For example, the core layer  102  is enveloped within a cladding comprising the first cladding layer  104  and second cladding layer  106  as shown in  FIG.  1   . 
     In some of such embodiments, the first glass composition of core layer  102  comprises a non-durable glass composition that is non-resistant to degradation in response to exposure to the reagent. The durable cladding can aid in protecting the core from exposure to the reagent. In other embodiments, the first glass composition comprises a durable glass composition that is resistant to degradation in response to exposure to the reagent. Thus, because the core is enveloped within the cladding, the first glass composition of the core of the durable glass article can comprise a durable or non-durable glass composition. In some embodiments, the core layer comprises the tinted layer, which can be non-durable, and the cladding layer serves to protect the tinted layer. Additionally, or alternatively, the core layer comprises a tinting agent that is reactive with air (e.g., Cu), and the cladding layer serves to prevent contacting the tinting agent with air at the surface of the glass article. 
     In various embodiments, a glass article can be used in applications in which strength and/or chemical durability are beneficial. For example, chemical durability can be beneficial for applications in which the glass will be used outdoors (e.g., automotive glass or architectural glass) or for other applications in which the glass article is likely to come into contact with potentially corrosive reagents such as acids or bases (e.g., laboratory benchtops). Strength can be beneficial in these same applications to avoid breakage of the glass article. 
     The first glass composition of core layer  102  and the second glass composition of first and/or second cladding layers  104  and  106  can comprise suitable glass compositions capable of forming a glass article with desired properties as described herein. Exemplary glass compositions and selected properties of the exemplary glass compositions can include those described in International Patent Application No. PCT/US2015/029671, which is incorporated by reference herein in its entirety. 
     In some exemplary embodiments, provided are laminate glass articles that may be tinted and/or textured. As used herein a “textured” laminate glass article comprises a surface roughness of at least about 400 Ra (u-inch), such as at least about 410 Ra (u-inch), at least about 420 Ra (u-inch), at least about 430 Ra (u-inch), at least about 440 Ra (u-inch), at least about 450 Ra (u-inch), at least about 460 Ra (u-inch), at least about 470 Ra (u-inch), at least about 480 Ra (u-inch), at least about 490 Ra (u-inch), or at least about 500 Ra (u-inch). Conversely, a “smooth surface” comprises a surface roughness of less than about 125 Ra (u-inch), such as less than about 120 Ra (u-inch), less than about 115 Ra (u-inch), or less than about 110 Ra (u-inch). For example, one or both cladding layers of the laminate glass article may be partially or completely textured using one or more textured rollers. In various embodiments, a textured laminate glass article may be formed by a method including: drawing a glass laminate (e.g., from an overflow distributor, a slot draw apparatus, a float bath, or another glass forming apparatus) including a glass core layer and at least one glass cladding layer thermally fused to the core layer; texturing the glass laminate by rolling a textured roller along a first surface of the glass laminate (e.g., an outer surface of the cladding layer) while a portion of the glass laminate contacting the textured roller has a temperature between the softening points of the cladding layer and the core layer (e.g., as the glass laminate is drawn); and cutting the textured glass laminate to form a textured laminate glass article. One or more of the core and cladding layers of the glass laminate may include a tinted glass composition, such as an alkali-free aluminosilicate glass composition described below. For example, a textured glass laminate may include: a tinted core layer and colorless cladding layers; a tinted core layer, a colorless first cladding layer, and a tinted second cladding layer; a tinted core layer, a tinted first cladding layer, and a tinted second cladding layer; a colorless core layer, a tinted first cladding layer, and a colorless second cladding layer; or a colorless core layer and tinted first and second cladding layers. Accordingly, a textured glass laminate may include any of the above tinted and/or colorless layers to create different composite tints. In some embodiments the core layer may have a higher softening point than the cladding layer, but the present disclosure is not limited thereto. Such a difference in softening point may enable the relatively more viscous or harder core layer to maintain the shape and/or stability of the laminate glass article during texturing of the relatively less viscous or softer cladding layer(s). 
     Alkali-Free Aluminosilicate Glass Composition 
     In various embodiments, provided are alkali-free aluminosilicate glass compositions that include copper as a tinting agent. In some embodiments, the glass compositions may be tinted in various colors. For example, the glass composition may be tinted blue, green, bluish green, or red. In other embodiments, the glass composition may include copper but may appear colorless or substantially colorless. The coloration of the glass composition may be achieved during glass formation, in at least some embodiments. In other embodiments, the glass composition may be achieved by reheating an annealed glass (e.g., by striking in). 
     The glass composition may be used as a core layer, a cladding layer, or any combination thereof of a glass laminate, such as the glass article  100  described above. For example, in some embodiments, the glass composition may be used to form a tinted core layer, a tinted cladding layer or layers, or a combination thereof, of the glass laminate. In other embodiments, the glass composition may be used to form a glass sheet that is not part of a laminate (e.g., a single-layer glass sheet). The glass composition may have anti-microbial properties, in some embodiments. The glass composition may be included in a glass article configured as a waveguide, in some embodiments. The glass composition may be formed using a fusion draw process, as described above. 
     In various embodiments, the glass composition may include a glass network former, one or more alkaline earth oxides, one or more redox agents, and copper. Exemplary compositional ranges are shown in Table 1 below. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Exemplary Glass Compositions 
               
            
           
           
               
               
               
               
            
               
                   
                 (Mol %) 
                 Min 
                 Max 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 Glass Network Former 
                 75 
                 94 
               
               
                   
                 Alkaline Earth Oxide 
                 7 
                 25 
               
               
                   
                 Cu/CuO 
                 0.5 
                 20 
               
               
                   
                 Redox Agent 
                 0 
                 7 
               
               
                   
                   
               
            
           
         
       
     
     As shown in Table 1, exemplary glass compositions may comprise from about 75 to about 94 mol % of a glass network former, such as from about 77 to about 93 mol %, from about 78 to about 92 mol %, or from about 80 to about 90 mol % of a glass network former. The glass network former may be a metal silicate. For example, the glass network former may include SiO 2  and Al 2 O 3 , or SiO 2 , Al 2 O 3 , and B 2 O 3 , or SiO 2 , Al 2 O 3 , and/or B 2 O 3 , and/or P 2 O 5 . 
     Exemplary glass compositions may include from about 7 to about 25 mol % of one or more alkaline earth oxides. For example, the glass composition may include from about 7.89 to about 24.5 mol %, from about 9 to about 24 mol %, or from about 10 to about 23 mol % of at least one alkaline earth oxide. In some embodiments, the alkaline earth oxide may be selected from the group consisting of MgO, CaO, SrO, BaO, and combinations thereof, for example. 
     Exemplary glass compositions may include from about 0.5 to about 20 mol % CuO. For example, the glass composition may include from about 0.5 to about 15 mol %, from about 0.5 to about 9 mol %, from about 0.5 to about 8 mol %, from about 0.5 to about 7, or from about 1 to about 4.5 mol % CuO. While component amounts are described with respect to CuO, copper may be included in an exemplary glass composition in any oxidation state. 
     Exemplary glass compositions may include from about 0 to about 7 mol % of a redox agent. For example, the glass composition may include from about 0 to about 6 mol %, from about 0.5 to about 6 mol %, from about 1 to about 5 mol %, or from about 1.5 to about 4.5 mol % of at least one redox agent. In some embodiments, the glass composition may also include a redox agent selected from SnO, SnO 2 , Sb 2 O 3 , As 2 O 3 , Ce 2 O 3 , Cl (e.g., derived from KCl or NaCl), ZrO 2 , C, or Fe 2 O 3 . For example, the glass composition may comprise one or more additional components selected from SnO 2 , charcoal, or a combination thereof. In some embodiments, the glass composition may include SnO and may be free of other redox agents such as Sb, As, S, C, or Ce. 
     The copper may be present in the glass composition as a colloidal metal and may operate as a tinting agent according to the oxidation state thereof. For example, in embodiments in which the redox agent comprises Sn, one or both of the following reactions can take place within the tinted layer to control the color thereof: 
       2Cu 2+ +Sn 2+ →2Cu 1+ +Sn 4+ ; and
 
       2Cu 1+ +Sn 2+ →2Cu 0 +Sn 4+ .
 
     While not wishing to be bound to a particular theory, it is believe that the color of the glass composition varies according to the oxidation state of the copper, which may be affected by other components of the glass composition acting as previously unrecognized reductants. This may be due at least in part to structural changes in the glass network. For example, the color of the glass composition may correspond to a ratio between the total amounts of Al 2 O 3  and B 2 O 3 , a total amount of alkaline earth metals RO, and an average ionic radius of the alkaline earth metals. For example, a mol % ratio of RO/Al 2 O 3  or RO/(Al 2 O 3 +B 2 O 3 ) may be used in conjunction with the average ionic radius of the alkaline earth metals, in order to predict the color of different glass compositions. In general the presence of RO/Al 2 O 3 &gt;1 and high average ionic radius may be associated with red coloration. All of these conditions in combination may lead to the reduction of copper cations to metallic copper. 
     According to various embodiments, a mol % ratio of RO/Al 2 O 3  may range from about 0.5 to about 5, such as from about 1 to about 4. In some embodiments, a mol % ratio of RO/(Al 2 O 3 +B 2 O 3 ) may range from about 0.1 to about 4.5, such as from about 0.2 to about 4. 
     In various embodiments, the glass composition may include trace amounts of other components, such as ZrO 2  or other inorganic components. 
     In some embodiments, the glass composition may have a blue tint. For example, the glass composition may have a blue color having L* a* b* coordinates of L*&lt;96, a*&lt;−1, and b*&lt;1. 
     In some embodiments, the glass composition may have a red tint. For example, the glass composition may have a red color having L* a* b* coordinates of L*&lt;96, a*&gt;0, and 0&lt;b*/a*&lt;1.5. 
     In some embodiments, the glass composition may have a green tint. For example, the glass composition may have a green color having L* a* b* coordinates of L*&lt;96, a*&lt;0, and b*&gt;0. 
     According to various embodiments, the glass composition may include compositional ranges and corresponding exemplary batch materials as shown in Table 2 below. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Exemplary Glass Compositions 
               
            
           
           
               
               
               
               
            
               
                   
                 (Mol %) 
                 Min 
                 Max 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 SiO 2   
                 45 
                 80 
               
               
                   
                 Al 2 O 3   
                 6 
                 22 
               
               
                   
                 B 2 O 3   
                 0 
                 25 
               
               
                   
                 MgO 
                 0 
                 9 
               
               
                   
                 CaO 
                 0 
                 22 
               
               
                   
                 SrO 
                 0 
                 22 
               
               
                   
                 BaO 
                 0 
                 22 
               
               
                   
                 SnO 2   
                 0 
                 6 
               
               
                   
                 CuO 
                 0.5 
                 20 
               
               
                   
                 C 
                 0 
                 0.5 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 2, exemplary glass compositions may comprise a glass network former selected from SiO 2 , Al 2 O 3 , B 2 O 3 , and combinations thereof. For example, the glass composition may include SiO 2  and Al 2 O 3  as glass network formers. In other embodiments, the glass composition may include SiO 2 , Al 2 O 3 , and B 2 O 3  as glass network formers. 
     In some embodiments, exemplary glass compositions may comprise from about 40 to about 80 mol % SiO 2 . In other embodiments the glass composition may include from about 45 to about 75 mol % SiO 2 , from about 50 to about 72 mol % SiO 2 , from about 60 to about 70 mol % SiO 2 , or from about 60 to about at least about 71 mol % SiO 2 . 
     Additionally, or alternatively, exemplary glass compositions may comprise from about 5 to about 22 mol % Al 2 O 3 . For example, the glass composition may include from about 6 to about at least about 21 mol % Al 2 O 3 , from about 7 to about 20 mol % Al 2 O 3 , from about 8 to about 18 mol % Al 2 O 3 , or from about 9 to about 15 mol % Al 2 O 3 . 
     In some embodiments, exemplary glass compositions may include 0 to 25 mol % B 2 O 3 . For example, the glass composition may include 0 to about 24 mol % B 2 O 3 , from about 1 to about 22 mol % B 2 O 3 , from about 5 to about 18 mol % B 2 O 3 , from about 6 to about 15 mol % B 2 O 3 , or from about 7 to about 12 mol % B 2 O 3 . In some embodiments, the glass composition may be free or substantially free of B 2 O 3 . 
     According to various embodiments, exemplary glass compositions may include an alkaline earth metal oxide, such as MgO, CaO, SrO, BaO, and combinations thereof. The alkaline earth metal oxides may be derived from nitrate, carbonate and/or pure oxide batch materials. 
     In various embodiments, exemplary glass compositions may include from 0 to about 9 mol % MgO. For example, the glass composition may include from 0 to 8 mol % MgO, from about 1 to about 7 mol % MgO, from about 2 to about 7 mol % MgO, or from about 3 to about 5 mol % MgO. 
     Additionally, or alternatively, exemplary glass compositions may include MgO, CaO, BaO, and/or SrO in amounts independently ranging from 0 to 22 mol %. For example, the glass composition may include MgO, CaO, BaO and/or SrO in amounts independently ranging from 0 to about 21 mol %, from about 1 to about 20 mol %, from about 2 to about 15 mol %, from about 3 to about 12 mol %, or from about 5 to about 10 mol %. 
     In various embodiments, exemplary glass compositions may include tin (SnO 2 ) and/or carbon (e.g., charcoal) as a redox agent. For example, the glass composition may include 0 to about 7 mol % tin, which may be added as a super addition. In other embodiments, the glass composition may include 0 to 6 mol %, from about 0.05 to about 5 mol %, from about 0.1 to about 5 mol %, from about 0.25 to about 4 mol %, or from about 0.5 to about 3 mol % tin. The tin may operate as a fining agent. In some embodiments, the glass composition may be free or substantially free of tin. The glass composition may optionally include from about 0 to about 1 mol %, such as from about 0 to about 0.5 mol % carbon (e.g., in the form of charcoal, sugar, starch, or other organic materials). 
     Exemplary glass compositions may include up to 20 mol % copper (CuO). The copper may or may not be included as a super addition. In various embodiments, the glass composition may include a relatively small amount of copper and still exhibit a desired color, as compared to conventional glass compositions that require a substantial amount of copper when used as a tinting agent. For example, in some embodiments the glass composition may include from about 0.1 to about 15 mol %, from about 0.25 to about 8 mol %, from about 0.5 to about 4.5 mol %, from about 0.75 to about 3 mol %, or from about 1 to about 2 mol % copper. 
     In some embodiments, glass compositions may have a ruby red color, when the glass composition includes Al 2 O 3 &lt;10 mol %, B 2 O 3 &lt;0.1 mol %, BaO&gt;2 mol %, SnO 2 &lt;1 mol %, and CuO&gt;0.5 mol %. Exemplary glass compositions may have a green color, when the glass composition includes Al 2 O 3 &gt;10 mol %, B 2 O 3 &gt;0 mol %, BaO≤10 mol %, SnO 2 &lt;0.1 mol %, CuO&gt;0.5 mol %. 
     Exemplary glass compositions may have a blue color, when the glass composition includes BaO&lt;10 mol %. Exemplary glass may have a blue color when oxidizing agents, such as nitrates, are included and/or reducing agents, such as carbon, are excluded from the glass batch materials. 
     In any of these embodiments, the glass composition may include other components in addition to those explicitly listed in amounts described herein. 
     According to various embodiments, the glass composition may be included in at least one layer of a glass article with the general configuration shown in  FIG.  1   . In particular, the glass composition may be used to form at least one tinted layer of the glass article, to thereby provide a tinted glass article. In some embodiments, the tinted layer may be the core layer. In this case, copper included in the glass composition may be protected from reacting with air and/or water. Additionally, or alternatively, the tinted core layer may give the glass article a 3D appearance or provide a depth of color not present in single layer tinted glass articles. In such embodiments, the cladding layers can be substantially colorless or tinted to enable a glass article with a desired color achieved by combining different colored cladding and core layers as described herein. 
     In some embodiments, the glass article described herein can be used as a first pane or ply in a glass-polymer laminate. For example, the glass-polymer laminate comprises the first pane and a second pane laminated to each other with a polymeric interlayer disposed therebetween. In some embodiments, the second pane comprises a second glass article as described herein. The second glass article can have the same or a different configuration than the glass article of the first pane. In other embodiments, the second pane comprises a single-layer glass sheet (e.g., an annealed glass sheet, a thermally strengthened glass sheet, or a chemically strengthened glass sheet) or a polymeric sheet (e.g., a polycarbonate sheet). The interlayer comprises poly vinyl butyral (PVB) or another suitable polymeric material. 
     In various embodiments, the glass articles described herein can be incorporated into vehicles such as automobiles, boats, and airplanes (e.g., glazing such as windshields, windows or sidelites, mirrors, pillars, side panels of a door, headrests, dashboards, consoles, or seats of the vehicle, or any portions thereof), architectural fixtures or structures (e.g., internal or external walls of building, and flooring), appliances (e.g., a refrigerator, an oven, a stove, a washer, a dryer, or another appliance), consumer electronics (e.g., televisions, laptops, computer monitors, and handheld electronics such as mobile phones, smart phones, tablets, and music players), furniture, information kiosks, retail kiosks, and the like. For example, the glass articles described herein can be used in display (e.g., cover glass, color filter, or glass backplane) and/or touch panel applications, whereby the glass article can enable a display and/or touch panel with desired attributes of the glass article such as curved shape, mechanical strength, etc. In some embodiments, such displays can comprise a micro-LED, an OLED, an LCD, a plasma cell, an electroluminescent (EL) cell array, or another suitable element configured to emit radiation. In other embodiments, such displays can comprise projection displays. For example, the glass article comprises light scattering features for displaying an image projected thereon. In another example, the glass articles described herein can be used in consumer electronics applications. For example, the glass articles can be used as part of a case for a mobile phone or smart phone (e.g., a back side of the device opposite the display). 
     In some embodiments, a display comprising a glass article described herein is at least partially transparent to visible light. Ambient light (e.g., sunlight) can make the display image difficult or impossible to see when projected on or generated by such a display. In some embodiments, the display, or portion thereof on which the display image is projected or from which the display image is emitted, can include a darkening material such as, for example, an inorganic or organic photochromic or electrochromic material, a suspended particle device, and/or a polymer dispersed liquid crystal. Thus, the transparency of the display can be adjusted to increase the contrast of the display image. For example, the transparency of the display can be reduced in bright sunlight by darkening the display to increase the contrast of the display image. The adjustment can be controlled automatically (e.g., in response to exposure of the display surface to a particular wavelength of light, such as ultraviolet light, or in response to a signal generated by a light detector, such as a photoeye) or manually (e.g., by a viewer). 
     The glass articles described herein can be used for a variety of applications including, for example, for cover glass, color filters, or glass backplane applications in consumer or commercial electronic devices including, for example, LCD, LED, microLED, OLED, and quantum dot displays, computer monitors, and automated teller machines (ATMs); for touch screen or touch sensor applications, for portable electronic devices including, for example, mobile telephones, personal media players, and tablet computers; for integrated circuit applications including, for example, semiconductor wafers; for photovoltaic applications; for architectural glass applications; for automotive or vehicular glass applications including, for example, glazing and displays; for commercial or household appliance applications; for lighting or signage (e.g., static or dynamic signage) applications; or for transportation applications including, for example, rail and aerospace applications. 
     EXAMPLES 
     Various embodiments will be further clarified by the following glass material examples. Glass sheets were formed by blending batch materials for one hour in a turbula mixer with media. The resultant mixture was melted in Pt crucibles at 1650° C., for 6 hours, in an electric furnace with an ambient air atmosphere. The resulting glass was annealed at temperatures ranging from about 725° C. to 770° C. Samples for transmission and color measurements were prepared by core drilling a 33 mm diameter piece from the annealed glass, and polishing the piece to a thickness of 0.7-0.8 mm. Color measurements were performed using an X-Rite Color i7 Benchtop Spectrophotometer, a reflectance/transmittance reference-level, dual beam sphere spectrophotometer that calculates percent transmission from 360 nm to 750 nm wavelengths and provides L*a*b* color coordinates for each measured sample. Color coordinates were calculated for D65 illuminant and 10 degree observer. Absorption (ABS) was calculated from the transmission data using the formula ABS=−log(T/100), where T is transmission in percent. 
     Example 1 
     Red tinted glass compositions were formed from batch materials shown in Table 3 below. The amounts of the various components are given in Table 3 as mol % on an oxide basis. Table 3 also includes L* a* b* color coordinates for selected glass compositions having thicknesses of 0.7 mm+/−0.1 mm. In addition, Table 3 provides total molar amounts of included alkaline earth metal oxides (RO) and ratios of the total RO amounts to molar amounts of Al 2 O 3  and (Al 2 O 3 +B 2 O 3 ). 
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Exemplary Red Glass Compositions 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 (Mol %) 
                 R1 
                 R2 
                 R3 
                 R4 
                 R5 
                 R6 
                 R7 
                 R8 
                 R9 
                 R10 
                 R11 
               
               
                   
               
               
                 SiO 2   
                 48.7 
                 62.3 
                 71.2 
                 66.3 
                 69.3 
                 67.3 
                 68.3 
                 68.3 
                 68.3 
                 69.3 
                 68.3 
               
               
                 Al 2 O 3   
                 9.6 
                 16 
                 7.75 
                 9.63 
                 6.63 
                 9.6 
                 9.6 
                 9.6 
                 6.1 
                 9.63 
                 9.6 
               
               
                 B 2 O 3   
                 18.6 
                 5 
                 1 
                 3 
                 3 
               
               
                 CaO (carbonate) 
                   
                   
                   
                 14.88 
                 14.88 
                   
                 6 
                 15 
                 17.5 
                 14.88 
                 18 
               
               
                 SrO (carbonate) 
                   
                   
                 10 
               
               
                 BaO (carbonate) 
                 22 
                 16 
                 10 
                 6.08 
                 6.08 
                 22 
                 15 
                 6 
                 7 
                 6.08 
                 3 
               
               
                 CuO 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
               
               
                 SnO 2   
                   
                   
                 0.1 
                 0.09 
                 0.09 
                 0.1 
                 0.1 
                 0.1 
                 0.1 
                 0.09 
                 0.1 
               
               
                 Color 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
               
               
                 L* 
                 24.12 
                 93.29 
                 2.16 
                 57.34 
                 28.42 
                 3.07 
                 6.59 
                 23.04 
                 1.73 
                 41.61 
                 95.55 
               
               
                 a* 
                 52.86 
                 1.13 
                 3.62 
                 40.39 
                 58.37 
                 19.42 
                 33.21 
                 53.77 
                 10.6 
                 59.63 
                 0.24 
               
               
                 b* 
                 39.14 
                 0.51 
                 0.72 
                 34.65 
                 48.1 
                 5.05 
                 11.05 
                 39.16 
                 2.72 
                 55.23 
                 1.28 
               
               
                 Total RO 
                 22 
                 16 
                 20 
                 20.96 
                 20.96 
                 22 
                 21 
                 21 
                 24.5 
                 20.96 
                 21 
               
               
                 RO/Al 2 O 3   
                 2.29 
                 1.00 
                 2.58 
                 2.18 
                 3.16 
                 2.29 
                 2.19 
                 2.19 
                 4.02 
                 2.18 
                 2.19 
               
               
                 RO/(B 2 O 3  + 
                 0.78 
                 0.76 
                 2.29 
                 1.66 
                 2.18 
                 2.29 
                 2.19 
                 2.19 
                 4.02 
                 2.18 
                 2.19 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 (Mol %) 
                 R12 
                 R13 
                 R14 
                 R15 
                 R16 
                 R17 
                 R18 
                 R19 
                 R20 
               
               
                   
               
               
                 SiO 2   
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
               
               
                 Al 2 O 3   
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
               
               
                 B 2 O 3   
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 CaO 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
               
               
                 CuO 
                 1.75 
                 6 
                 6 
                 7 
                 7 
                 7 
                 8 
                 5 
                 5 
               
               
                 SnO2 
                 5.25 
                 1 
                 2 
                 0 
                 1 
                 2 
                 2 
                 1 
                 2 
               
               
                 Color 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
                 red 
               
               
                 Total RO 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
               
               
                 RO/Al 2 O 3   
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
               
               
                 RO/(B 2 O 3  + 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 (Mol %) 
                 R21 
                 R22 
                 R23 
                 R24 
                 R25 
                 R26 
               
               
                   
               
               
                 SiO 2   
                 68 
                 68 
                 58.55 
                 58.55 
                 58.55 
                 58.55 
               
               
                 Al 2 O 3   
                 11 
                 11 
                 8.53 
                 8.53 
                 8.53 
                 8.53 
               
               
                 B 2 O 3   
                 10 
                 10 
                 25 
                 25 
                 25 
                 25 
               
               
                 CaO 
                 11 
                 11 
                 7.89 
                 7.89 
                 7.89 
                 7.89 
               
               
                 CuO 
                 4 
                 4 
                 5 
                 10 
                 15 
                 20 
               
               
                 SnO2 
                 1.5 
                 2 
                 0.1 
                 0.1 
                 0.1 
                 0.1 
               
               
                 Color 
                 red/phase sep 
                 red/phase sep 
                 red 
                 red 
                 red 
                 red 
               
               
                 Total RO 
                 11 
                 11 
                 7.89 
                 7.89 
                 7.89 
                 7.89 
               
               
                 RO/Al 2 O 3   
                 1 
                 1 
                 0.92 
                 0.92 
                 0.92 
                 0.92 
               
               
                 RO/(B 2 O 3  + 
                 0.52 
                 0.52 
                 0.24 
                 0.24 
                 0.24 
                 0.24 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
            
           
         
       
     
       FIG.  3    is a graph illustrating the absorbance spectra of red-tinted glass compositions R10 and R11. As can be seen in  FIG.  3   , the red-tinted glass compositions R10 and R11 had a local absorbance maximum at 550-570 nm, and an absorbance that was less in the 600-700 nm wavelength range than in the 350-550 nm wavelength range. 
     Example 2 
     Blue tinted glass compositions shown in Table 4 were formed as noted above. The amounts of the various components are given in Table 4 as mol % on an oxide basis. Table 4 also includes L* a* b* color coordinates for selected glass compositions having thicknesses of 0.7 mm+/−0.1 mm. In addition, Table 4 provides total molar amounts of included alkaline earth metal oxides (RO) and ratios of the total RO amounts to molar amounts of Al 2 O 3  and (Al 2 O 3 +B 2 O 3 ). 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Exemplary Blue Tinted Glass Compositions 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 (Mol %) 
                 B1 
                 B2 
                 B3 
                 B4 
                 B5 
                 B6 
                 B7 
                 B8 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 SiO 2   
                 68 
                 48.7 
                 67.3 
                 69.3 
                 66.95 
                 67.3 
                 68.95 
                 71.15 
               
               
                 Al 2 O 3   
                 10 
                 9.6 
                 9.6 
                 9.63 
                 10.49 
                 9.6 
                 10.49 
                 7.75 
               
               
                 B 2 O 3   
                   
                 18.6 
                   
                   
                   
                   
                   
                 0.99 
               
               
                 CaO (nitrate) 
               
               
                 CaO 
                   
                 22 
                   
                 14.88 
                 14.04 
                   
                 13.04 
               
               
                 (carbonate) 
               
               
                 SrO (nitrate) 
                   
                   
                 0.5 
                   
                   
                   
                   
                 0.5 
               
               
                 SrO 
                   
                   
                 22 
                   
                   
                 22 
                   
                 9.98 
               
               
                 (carbonate) 
               
               
                 BaO (nitrate) 
                 0.5 
                   
                   
                 6.08 
               
               
                 BaO 
                 21.5 
                   
                   
                   
                 7.94 
                   
                 6.94 
                 9.98 
               
               
                 (carbonate) 
               
               
                 SnO 2   
                 0.1 
                   
                 0.1 
                 0.09 
                 0.08 
                 0.1 
                 0.08 
                 0.1 
               
               
                 CuO 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
               
               
                 Color 
                 blue 
                 blue 
                 blue 
                 blue 
                 blue 
                 blue 
                 blue 
                 blue 
               
               
                 L* 
                 91.39 
                 90.51 
                 91.03 
                 92.99 
                 90.61 
                 91.14 
                 91.68 
                 90.57 
               
               
                 a* 
                 −5.45 
                 −7.31 
                 −5.92 
                 −4.08 
                 −5.93 
                 −6.01 
                 −4.58 
                 −7.18 
               
               
                 b* 
                 −1.34 
                 −0.29 
                 −1.1 
                 0.75 
                 0.45 
                 −1.59 
                 0.86 
                 −1.95 
               
               
                 Total RO 
                 22 
                 22 
                 22.5 
                 20.96 
                 21.98 
                 22 
                 19.98 
                 20.01 
               
               
                 RO/Al 2 O 3   
                 2.2 
                 2.29 
                 2.34 
                 2.18 
                 2.1 
                 2.29 
                 1.9 
                 2.58 
               
               
                 RO/(B 2 O 3  + 
                 2.2 
                 0.78 
                 2.34 
                 2.18 
                 2.1 
                 2.29 
                 1.9 
                 2.29 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
            
           
         
       
     
       FIG.  4    is a graph illustrating the absorbance spectrum of blue-tinted glass compositions B1 and B8. As can be seen in  FIG.  4   , the blue-tinted glass compositions B1 and B8 had an absorbance minimum between about 450 nm and about 550 nm, which provides a greenish blue or blue coloration. 
     Example 3 
     Green tinted glass compositions shown in Table 5 were formed as noted above. The amounts of the various components are given in Table 5 as mol % on an oxide basis. Table 5 also includes L* a* b* color coordinates for selected glass compositions having thicknesses of 0.7 mm+/−0.1 mm. In addition, Table 5 provides total molar amounts of included alkaline earth metal oxides (RO) and ratios of the total RO amounts to molar amounts of Al 2 O 3  and (Al 2 O 3 +B 2 O 3 ). 
     
       
         
           
               
             
               
                 TABLE 5 
               
               
                   
               
               
                 Exemplary Green Tinted Glass Compositions 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 (Mol %) 
                 G1 
                 G2 
                 G3 
                 G4 
                 G5 
                 G6 
                 G7 
                 G8 
                 G9 
               
               
                   
               
               
                 SiO 2   
                 68 
                 67.3 
                 64.8 
                 62.3 
                 68.3 
                 67.3 
                 68.3 
                 69.95 
                 67.3 
               
               
                 Al 2 O 3   
                 10 
                 16 
                 16 
                 16 
                 15.3 
                 9.6 
                 9.6 
                 9.49 
                 22 
               
               
                 B 2 O 3   
                   
                   
                 2.5 
                 5 
               
               
                 CaO (nitrate) 
                 0.5 
                   
                   
                   
                 0.5 
                   
                 0.5 
               
               
                 CaO (carbonate) 
                 21.5 
                 16 
                 16 
                 16 
                 10.9 
                 22 
                 15 
                 13.04 
               
               
                 BaO (nitrate) 
               
               
                 BaO (carbonate) 
                   
                   
                   
                   
                 6 
                   
                 6 
                 6.94 
                 10 
               
               
                 SnO 2   
                 0.1 
                   
                   
                   
                 0.1 
                 0.1 
                 0.1 
                 0.08 
                 0.1 
               
               
                 CuO 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
               
               
                 Color 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
               
               
                 L* 
                 90.8 
                 91.76 
                 92.03 
                 91.53 
                 92.14 
                 93.58 
                 91.32 
                 90.84 
                 91.01 
               
               
                 a* 
                 −5.14 
                 −3.08 
                 −3.32 
                 −4.09 
                 −2.77 
                 −2.44 
                 −4.95 
                 −5.41 
                 −0.94 
               
               
                 b* 
                 2.49 
                 4.57 
                 3.84 
                 3.71 
                 3.67 
                 2.63 
                 1.32 
                 1.01 
                 0.78 
               
               
                 Total RO 
                 22 
                 16 
                 16 
                 16 
                 17.4 
                 22 
                 21.5 
                 19.98 
                 10 
               
               
                 RO/Al 2 O 3   
                 2.2 
                 1 
                 1 
                 1 
                 1.14 
                 2.29 
                 2.24 
                 2.11 
                 0.45 
               
               
                 RO/(B 2 O 3  + 
                 2.20 
                 1.00 
                 0.86 
                 0.76 
                 1.14 
                 2.29 
                 2.24 
                 2.11 
                 0.45 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
               
                 (Mol %) 
                 G10 
                 G11 
                 G12 
                 G13 
                 G14 
                 G15 
                 G16 
                 G17 
                 G18 
               
               
                   
               
               
                 SiO 2   
                 68.95 
                 68.95 
                 68.95 
                 68.95 
                 68.95 
                 68.95 
                 68.95 
                 68.95 
                 69.17 
               
               
                 Al 2 O 3   
                 10.49 
                 10.49 
                 10.49 
                 10.49 
                 10.49 
                 10.49 
                 10.49 
                 10.49 
                 10.51 
               
               
                 B 2 O 3   
                 9.89 
                 9.89 
                 9.89 
                 9.89 
                 4.89 
                 9.89 
                 9.89 
                 9.89 
                 9.53 
               
               
                 MgO (pure) 
                 2 
                   
                   
                 8.09 
                   
                   
                   
                   
                 2.01 
               
               
                 CaO (carbonate) 
                 8.09 
                 8.09 
                 8.09 
                   
                 10.59 
                 10.09 
                   
                   
                 8.13 
               
               
                 SrO (carbonate) 
                   
                 2 
                   
                   
                   
                   
                 10.09 
                   
                 0.56 
               
               
                 BaO (carbonate) 
                   
                   
                 2 
                 2 
                 4.5 
                   
                 0 
                 10.09 
               
               
                 SnO 2   
                 0.08 
                 0.08 
                 0.08 
                 0.08 
                 0.08 
                 0.08 
                 0.08 
                 0.08 
                 0.08 
               
               
                 CuO 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
               
               
                 Color 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
               
               
                 L* 
                 94.67 
                 94.84 
                 95.1 
                 95.51 
                 93.06 
                 94.44 
                 94.24 
                 94.26 
                 94.3 
               
               
                 a* 
                 −1.96 
                 −1.59 
                 −1.42 
                 −1.51 
                 −3.38 
                 −1.93 
                 −1.76 
                 −1.62 
                 −2.16 
               
               
                 b* 
                 1.8 
                 2.04 
                 1.88 
                 0.67 
                 1.49 
                 2.35 
                 1.98 
                 2.24 
                 2.38 
               
               
                 Total RO 
                 10.09 
                 10.09 
                 10.09 
                 10.09 
                 15.09 
                 10.09 
                 10.09 
                 10.09 
                 10.7 
               
               
                 RO/Al 2 O 3   
                 0.96 
                 0.96 
                 0.96 
                 0.96 
                 1.44 
                 0.96 
                 0.96 
                 0.96 
                 1.02 
               
               
                 RO/(B 2 O 3  + 
                 0.5 
                 0.5 
                 0.5 
                 0.5 
                 0.98 
                 0.5 
                 0.5 
                 0.5 
                 0.53 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 (Mol %) 
                 G19 
                 G20 
                 G21 
                 G22 
                 G23 
                 G24 
                 G25 
                 G26 
                 G27 
                 G28 
                 G29 
                 G30 
               
               
                   
               
               
                 SiO 2   
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
               
               
                 Al 2 O 3   
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 8 
               
               
                 B 2 O 3   
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 CaO 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 14 
               
               
                 CuO 
                 1 
                 1.25 
                 1.5 
                 1 
                 1.25 
                 1.5 
                 1.75 
                 3 
                 6 
                 8 
                 8 
                 0.5 
               
               
                 SnO 2   
                 3 
                 3.75 
                 4.5 
                 2 
                 2.5 
                 3 
                 3.5 
                 3 
                 0 
                 0 
                 1 
                 0 
               
               
                 Color 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
               
               
                 Total RO 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 14 
               
               
                 RO/Al 2 O 3   
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1.75 
               
               
                 RO/(B 2 O 3  + 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.78 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 (Mol %) 
                 G31 
                 G32 
                 G33 
                 G34 
                 G35 
                 G36 
                 G37 
                 G38 
                 G39 
                 G40 
                 G41 
               
               
                   
               
               
                 SiO 2   
                 68 
                 68 
                 70 
                 62 
                 54 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
               
               
                 Al 2 O 3   
                 10 
                 14 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
               
               
                 B 2 O 3   
                 10 
                 10 
                 8 
                 16 
                 24 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 CaO 
                 12 
                 8 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
               
               
                 CuO 
                 0.5 
                 0.5 
                 0.5 
                 0.5 
                 0.5 
                 2 
                 2 
                 2 
                 3 
                 3 
                 3 
               
               
                 SnO 2   
                 0 
                 0 
                 0 
                 0 
                 0 
                 1 
                 1.5 
                 2 
                 1 
                 1.5 
                 2 
               
               
                 Color 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
               
               
                 Total RO 
                 12 
                 8 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
               
               
                 RO/Al 2 O 3   
                 1.2 
                 0.6 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
               
               
                 RO/(B 2 O 3  + 
                 0.6 
                 0.33 
                 0.58 
                 0.41 
                 0.31 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 (Mol %) 
                 G42 
                 G43 
                 G44 
                 G45 
                 G46 
                 G47 
                 G48 
                 G49 
                 G50 
                 G51 
               
               
                   
               
               
                 SiO 2   
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 68 
                 58.55 
               
               
                 Al 2 O 3   
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 8.53 
               
               
                 B 2 O 3   
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 25 
               
               
                 CaO 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 7.89 
               
               
                 CuO 
                 4 
                 0.5 
                 0.5 
                 1 
                 1 
                 1 
                 2 
                 2 
                 2 
                 1 
               
               
                 SnO 2   
                 1 
                 0.1 
                 0.2 
                 0.1 
                 0.2 
                 0.5 
                 0.1 
                 0.2 
                 0.5 
                 0.1 
               
               
                 Color 
                 green/ 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
               
               
                   
                 phase sep 
               
               
                 Total RO 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 11 
                 7.89 
               
               
                 RO/Al 2 O 3   
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 0.93 
               
               
                 RO/(B 2 O 3  + 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.52 
                 0.24 
               
               
                 Al 2 O 3 ) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                   
                 (Mol %) 
                 G52 
                 G53 
                 G54 
                 G55 
                 G56 
                 G57 
                 G58 
               
               
                   
                   
               
               
                   
                 SiO 2   
                 69.3 
                 68.3 
                 67.3 
                 69.3 
                 68.3 
                 69.3 
                 68.3 
               
               
                   
                 Al 2 O 3   
                 9.6 
                 15.3 
                 16 
                 9.6 
                 15.3 
                 9.6 
                 15.3 
               
               
                   
                 B 2 O 3   
               
               
                   
                 MgO 
                 6 
                 4.4 
                 16 
               
               
                   
                 La 2 O 3   
                   
                   
                   
                 3 
                 2.2 
               
               
                   
                 PbO 
                   
                   
                   
                   
                   
                 6 
                 4.4 
               
               
                   
                 CaO (carbonate) 
                 15 
                 10.9 
                   
                 15 
                 10.9 
                 15 
                 10.9 
               
               
                   
                 SnO 2   
                 0.1 
                 0.1 
                   
                 0.1 
                 0.1 
                 0.1 
                 0.1 
               
               
                   
                 CuO 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
                 1 
               
               
                   
                 Color 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
                 green 
               
               
                   
                 L 
                 92.72 
                 93.93 
                 91.71 
                 92.07 
                 93.44 
                 92.17 
                 93.67 
               
               
                   
                 a 
                 −3.48 
                 −2.24 
                 −5.92 
                 −3.69 
                 −2.17 
                 −4.58 
                 −6.85 
               
               
                   
                 b 
                 3.06 
                 2.8 
                 1.16 
                 2.71 
                 3.05 
                 13.63 
                 8.46 
               
               
                   
                 Total RO 
                 21 
                 15.3 
                 16 
                 15 
                 10.9 
                 15 
                 10.9 
               
               
                   
                 RO/Al 2 O 3   
                 2.19 
                 1 
                 1 
                 1.56 
                 0.71 
                 1.56 
                 0.71 
               
               
                   
                 RO/(B 2 O 3  + 
                 2.19 
                 1 
                 1 
                 1.56 
                 0.71 
                 1.56 
                 0.71 
               
               
                   
                 Al 2 O 3 ) 
               
               
                   
                   
               
            
           
         
       
     
       FIG.  5    is a graph illustrating the absorbance spectrum of green-tinted glass compositions G1 and G12. As can be seen in  FIG.  5   , the glass compositions G1 and G12 had an absorbance minimum between about 495 to about 570 nm, which provides a greenish coloration. 
     Example 4 
     Substantially colorless glass was prepared from a batched composition C4, including in mol %: 68.9 SiO 2 , 10.5 Al 2 O 3 , 9.9 B 2 O 3 , 10.1 SrO (as strontium carbonate), 0.1 SnO 2 , 1 CuO, and 0.5 C (as charcoal). L*a*b* color coordinates and transmission were measured on a sample 0.7 mm+/−0.1 mm in thickness as: L*=96.67, a*=−0.08, b*=0.44. The absorbance spectrum of substantially colorless glass C4 is shown in  FIGS.  3 ,  4 , and  5   . C4 had an absorbance of less than 0.08 and an absorbance delta (e.g., a difference between maximum and minimum absorbance) of less that about 0.01 at wavelengths from about 400 to about 750 nm, which provides a substantially colorless composition. 
     Example 5 
     Red tinted glass compositions shown in Table 7 were formed as noted above, except that coloration was provided by reheating (e.g., striking-in) the glass to a temperature within +/−50 deg C. of the annealing point for a time of 0.5 hours to 24 hours. after the glass compositions were annealed. The amounts of the various components are given in Table 7 as mol % on an oxide basis. Table 7 also includes L* a* b* color coordinates for selected glass compositions having thicknesses of 0.7 mm+/−0.1 mm, before the reheating process was performed. In addition, Table 6 provides total molar amounts of included alkaline earth metal oxides (RO) and ratios of the total RO amounts to molar amounts of Al 2 O 3  and (Al 2 O 3 +B 2 O 3 ). 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Exemplary Red Strike-in Glass Compositions 
               
            
           
           
               
               
               
               
               
            
               
                 (Mol %) 
                 RS1 
                 RS2 
                 RS3 
                 RS4 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 SiO 2   
                 67.3 
                 68.95 
                 68.95 
                 68.3 
               
               
                 Al 2 O 3   
                 9.6 
                 10.49 
                 10.49 
                 9.6 
               
               
                 B 2 O 3   
                   
                 9.89 
               
               
                 CaO (carbonate) 
                 22 
                 10.09 
                 13.04 
               
               
                 SrO (carbonate) 
                   
                   
                   
                 15 
               
               
                 BaO (carbonate) 
                   
                   
                 6.94 
                 6 
               
               
                 SnO 2   
                 0.1 
                 0.1 
                 0.08 
                 0.1 
               
               
                 CuO 
                 1 
                 1 
                 1 
                 1 
               
               
                 C 
                 0.5 
                 0.5 
               
               
                 Color 
                 colorless/strike- 
                 colorless/strike- 
                 colorless/strike- 
                 colorless/strike- 
               
               
                   
                 in red 
                 in red 
                 in red 
                 in red 
               
               
                 L* 
                 96.32 
                 96.64 
                 94.47 
                 96.47 
               
               
                 a* 
                 −0.36 
                 −0.09 
                 −0.34 
                 −0.24 
               
               
                 b* 
                 0.41 
                 0.37 
                 0.14 
                 0.44 
               
               
                 Total RO 
                 22 
                 10.09 
                 19.98 
                 21 
               
               
                 RO/Al 2 O 3   
                 2.29 
                 0.96 
                 1.90 
                 2.19 
               
               
                 RO/(B 2 O 3  + Al 2 O 3 ) 
                 2.29 
                 0.5 
                 1.90 
                 2.19 
               
               
                   
               
            
           
         
       
     
       FIG.  6    is a graph showing color coordinates for blue, green and colorless glasses. As shown in  FIG.  6   , the blue glasses had a* coordinates ranging from about −4 to about −7.5, and b* coordinates ranging from about −2 to about 1. The green glasses had a* coordinates ranging from about −5.5 to about −1, and b* coordinates ranging from about 1 to about 5. The colorless glass had a* and b* coordinates of about (0, 0.25). 
       FIG.  7    is a graph showing color coordinates for red glasses. Referring to  FIG.  7   , the red glasses had a* coordinates ranging from about 1 to about 60, and b* coordinates ranging from about 0 to about 55. 
     It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.