Patent Description:
Electronic devices such as notebook computers, personal digital assistants (PDAs), portable navigation device (PNDs), media players, mobile phones, portable inventory devices (PIDs), and other portable computing devices have converged while at the same time becoming small, light, and functionally more powerful. One factor contributing to the development and availability of such smaller devices is an ability to increase computational density and operating speed by ever decreasing electronic component sizes. Another factor contributing toward increasing functionality of portable computing devices is an increasing reliance on wireless communication capability (e.g., with microwave and RF frequencies). However, the trend toward smaller, lighter, and more functionally powerful electronic devices presents a continuing challenge regarding design of some components of the portable computing devices.

Components associated with the portable computing devices encountering particular design challenges include the enclosure or housing used to house the various internal/electronic components. One design challenge associated with these enclosures and housings is that they should be transparent to the wireless communication frequencies of the enclosed electronic components. Another design challenge generally arises from two conflicting design goals-the desirability of making the enclosure or housing lighter and thinner, and the desirability of making the enclosure or housing stronger and more rigid. Lighter enclosures or housings, typically thin plastic structures with few fasteners, tend to be more flexible while having a tendency to buckle and bow as opposed to stronger and more rigid enclosure or housings, typically thicker plastic structures with more fasteners having more weight. Unfortunately, plastics are soft materials that are easily scratched and scuffed degrading their appearance.

Glass-ceramics are used widely in various other applications, and are known to be much harder and more scratch resistant than polymers. For example, glass-ceramics are used widely in kitchens as cooktops, cookware, and eating utensils, such as bowls, dinner plates, and the like. As another example, transparent glass-ceramics are used in the production of oven and/or furnace windows, and the like. Nevertheless, these oven- and furnace-oriented glass-ceramics, while having high hardness and scratch resistance are not generally understood as having the desired combination of mechanical properties (e.g., strength) and/or optical properties (e.g., transparency to wireless communication frequencies) suitable for an electronic device housing. Other glasses and glass-ceramics, while suitable for some applications with similar requirements (e.g., optical filters, ophthalmic lenses, aesthetic- and artistic-driven glass applications), contain materials (e.g., cadmium, selenium, and others) that are highly-regulated (and therefore costly or otherwise not practical to manufacture) under federal law, including the Resource Conservation and Recovery Act (RCRA). In addition, other known 'dark' glasses and glass-ceramics that may also be suitable for these same applications, require heat treatments at substantially high temperatures and long durations, and have not been viable in fusion-forming processes.

Accordingly, there exists a need for glass and glass-ceramic materials, compositions and articles, as well as glass and glass-ceramic technologies, that provide improved choices and/or lower manufacturing costs for enclosures or housings of portable computing devices and for components of optical filters, ophthalmic lenses, aesthetic applications, and other applications with similar mechanical and optical property requirements.

<CIT> relates to intermediate to high CTE glasses. <CIT> relates to methods for preparing borosilicate glass containing nuclear waste. <CIT> relates to laminate glass articles with UV- and NIR-blocking characteristics. <CIT> relates to glass-ceramics and glasses. <CIT> relates to glass ceramics and glass-ceramic articles with UV- and NIR-blocking characteristics.

The invention relates to an article comprising: SiO<NUM> from <NUM> mol% to <NUM> mol%; Al<NUM>O<NUM> from <NUM> mol% to <NUM> mol%; B<NUM>O<NUM> from <NUM> mol% to <NUM> mol%; WO<NUM> plus MoOs from <NUM> mol% to <NUM> mol%; Fe<NUM>O<NUM> plus MnO<NUM> from <NUM> mol% to <NUM> mol%; and R<NUM>O from <NUM> mol% to <NUM> mol%. The R<NUM>O is one or more of Li<NUM>O, Na<NUM>O, K<NUM>O, Rb<NUM>O and Cs<NUM>O. Further, R<NUM>O - Al<NUM>O<NUM> ranges from -<NUM> mol% to +<NUM> mol%.

The following is a description of the figures in the accompanying drawings. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

Additional features and advantages of the invention will be set forth in the detailed description which follows and will be apparent to those skilled in the art from the description, or recognized by practicing the invention as described in the following description, together with the claims and appended drawings.

In this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions.

Modifications of the disclosure will occur to those skilled in the art and to those who make or use the disclosure. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the disclosure, which is defined by the following claims, as interpreted according to the principles of patent law, including the doctrine of equivalents.

It will be understood by one having ordinary skill in the art that construction of the described disclosure, and other components, is not limited to any specific material.

As used herein, the term "about" means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term "about" is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. Whether or not a numerical value or end-point of a range in the specification recites "about," the numerical value or end-point of a range is intended to include two embodiments: one modified by "about," and one not modified by "about. " It will be further understood that the end-points of each of the ranges are significant both in relation to the other end-point, and independently of the other end-point.

Unless otherwise specified, all compositions are expressed in terms of as-batched mole percent (mol%). As will be understood by those having ordinary skill in the art, various melt constituents (e.g., fluorine, alkali metals, boron, etc.) may be subject to different levels of volatilization (e.g., as a function of vapor pressure, melt time and/or melt temperature) during melting of the constituents. As such, the as-batched mole percent values used in relation to such constituents are intended to encompass values within ±<NUM> mol% of these constituents in final, as-melted articles. With the forgoing in mind, substantial compositional equivalence between final articles and as-batched compositions is expected.

For purposes of this disclosure, the terms "bulk," "bulk composition" and/or "overall compositions" are intended to include the overall composition of the entire article, which may be differentiated from a "local composition" or "localized composition" which may differ from the bulk composition owing to the formation of crystalline and/or ceramic phases.

As also used herein, the terms "article," "glass-article," "ceramic-article," "glass-ceramics," "glass elements," "glass-ceramic article" and "glass-ceramic articles" may be used interchangeably, and in their broadest sense, to include any object made wholly or partly of glass and/or glass-ceramic material.

As used herein, a "glass state" refers to an inorganic amorphous phase material within the articles of the disclosure that is a product of fusion that has cooled to a rigid condition without crystallizing. As used herein, a "glass-ceramic state" refers to an inorganic material within the articles of the disclosure which includes both the glass state and a "crystalline phase" and/or "crystalline precipitates" as described herein.

As used herein, "transmission", "transmittance", "optical transmittance" and "total transmittance" are used interchangeably in the disclosure and refer to external transmission or transmittance, which takes absorption, scattering and reflection into consideration. Fresnel reflection is not subtracted out of the transmission and transmittance values reported herein. In addition, any total transmittance values referenced over a particular wavelength range are given as an average of the total transmittance values measured over the specified wavelength range. Further, as also used herein, "average absorbance" is given as (<NUM> - log(average transmittance, %))/path length.

As used herein, "optical density units", "OD" and "OD units" are used interchangeably in the disclosure to refer to optical density units, as commonly understood as a measure of absorbance of the material tested, as measured with a spectrometer given by OD= -log (I/I<NUM>) where I<NUM> is the intensity of light incident on the sample and I is the intensity of light that is transmitted through the sample. Further, the terms "OD/mm" or "OD/cm" used in this disclosure are normalized measures of absorbance, as determined by dividing the optical density units (i.e., as measured by an optical spectrometer) by the thickness of the sample (e.g., in units of millimeters or centimeters). In addition, any optical density units referenced over a particular wavelength range (e.g., <NUM> OD/mm to <NUM> OD/mm in UV wavelengths from <NUM> to <NUM>) are given as an average value of the optical density units over the specified wavelength range.

As also used herein, the terms "sharp cutoff wavelength" and "cutoff wavelength" are interchangeably used in the disclosure and refer to a cutoff wavelength within a range of <NUM> to <NUM> in which the glass-ceramic has a substantially higher transmittance above the cutoff wavelength (λc) in comparison to its transmittance below the cutoff wavelength (λc). The cutoff wavelength (λc) is the wavelength at the midpoint between an "absorption limit wavelength" and a "high transmittance limit wavelength" in the given spectra for the glass-ceramic. The "absorption limit wavelength" is specified as the wavelength in which the transmittance is <NUM>%; and the "high transmittance wavelength" is defined as the wavelength in which the transmittance is <NUM>%.

As used herein, the term "haze" refers to the percentage of transmitted light scattered outside an angular cone of ±<NUM>° in a sample having a transmission path of <NUM> and measured in accordance with ASTM procedure D1003.

As it relates to the glass-ceramic and glass-ceramic materials and articles of the disclosure, compressive stress and depth of compression ("DOC") are measured by evaluating surface stress using commercially available instruments, such as the scattered light polariscope SCALP220 and accompanying software version <NUM> manufactured by GlasStress, Ltd. (Tallinn, Estonia), or the FSM-<NUM>, manufactured by Orihara Co. (Tokyo, Japan), unless otherwise noted herein. Both instruments measure optical retardation which must be converted to stress via the stress optic coefficient ("SOC") of the material being tested. Thus, stress measurements rely upon the accurate measurement of the SOC, which is related to the birefringence of the glass. SOC in turn is measured according to a modified version of Procedure C, which is described in ASTM standard C770-<NUM> (<NUM>) ("modified Procedure C"), entitled "Standard Test Method for Measurement of Glass Stress-Optical Coefficient". The modified Procedure C includes using a glass or glass-ceramic disc as the specimen having a thickness of <NUM> to <NUM> and a diameter of <NUM>. The disc is isotropic and homogeneous, and is core-drilled with both faces polished and parallel. The modified Procedure C also includes calculating the maximum force, Fmax, to be applied to the disc. The force should be sufficient to produce at least <NUM> MPa compression stress. Fmax is calculated using the equation: <MAT> where Fmax is the maximum force (N), D is the diameter of the disc (mm), and h is the thickness of the light path (mm). For each force applied, the stress is computed using the equation: <MAT> where F is the force (N), D is the diameter of the disc (mm), and h is the thickness of the light path (mm).

Unless otherwise noted herein, the term "substantially free" means that the specified element or constituent (e.g., Cd, Se) is not intentionally or purposefully included in the referenced glass, glass-ceramic or article, and that any measurable amounts of the specified element or constituent are present at < <NUM> ppm.

Articles of the present disclosure are composed of glass and/or glass-ceramics having one or more of the compositions outlined herein. The articles have scratch resistance, strength, light weight, relatively low processing costs, and particular optical properties suitable for use as housing and structural components in portable electronic devices and as optical elements and filters. As such, the articles of the disclosure can be employed in any number of applications. For example, the articles can be employed in the form of substrates, filters, elements, lenses, covers and/or other elements in any number of optics-related and/or aesthetic applications. As another example, the articles can be employed as housings, covers, enclosures and the like for notebook computers, personal digital assistants (PDAs), portable navigation device (PNDs), media players, mobile phones, portable inventory devices (PIDs), and other portable computing devices.

In general, the articles of the disclosure are formed from an as-batched composition and are cast in a glass state. The articles may later be annealed and/or thermally processed (e.g., heat treated) to form a glass-ceramic state having a plurality of ceramic or crystalline particles, precipitates and the like. It will be understood that depending on the casting technique employed, the volume of glass cast, and the casting geometry, the article may readily crystallize and become a glass-ceramic without additional heat treatment (e.g., essentially be cast into the glass-ceramic state). In examples where a post-forming thermal processing is employed, a portion, a majority, substantially all or all of the article may be converted from the glass state to the glass-ceramic state. As such, although compositions of the article may be described in connection with the glass state and/or the glass-ceramic state, the bulk composition of the article may remain substantially unaltered when converted between the glass and glass-ceramic states, despite localized portions of the article having different compositions (i.e., owing to the formation of the ceramic or crystalline precipitates).

The article includes Al<NUM>O<NUM>, SiO<NUM>, B<NUM>O<NUM>, WO<NUM> and/or MO<NUM>, Fe<NUM>O<NUM> and/or MnO<NUM>, and may include R<NUM>O where R<NUM>O is one or more of Li<NUM>O, Na<NUM>O, K<NUM>O, Rb<NUM>O and Cs<NUM>O. Further, the article can include RO where RO is one or more of MgO, CaO, SrO, BaO and ZnO and/or a number of dopants. It will be understood that a number of other constituents (e.g., F, As, Sb, Ti, P, Ce, Eu, La, Cl, Br, SnO<NUM>, etc.) can be included in the article without departing from the teachings provided herein.

Referring now to <FIG>, an article <NUM> is depicted that includes a substrate <NUM> having a glass and/or glass-ceramic composition according to the disclosure. The article <NUM> can be employed in any number of applications. For example, the article <NUM> and/or substrate <NUM> can be employed in the form of substrates, elements, covers and other elements in any number of optics related and/or aesthetic applications.

The substrate <NUM> defines or includes a pair of opposing primary surfaces <NUM> and <NUM>. In some examples of the article <NUM>, the substrate <NUM> includes a compressive stress region <NUM>. As shown in <FIG>, the compressive stress region <NUM> extends from the primary surface <NUM> to a first selected depth <NUM> in the substrate. In some examples, the substrate <NUM> includes a comparable compressive stress region <NUM> that extends from the primary surface <NUM> to a second selected depth (not shown). Further, in some examples, multiple compressive stress regions <NUM> may extend from the primary surfaces <NUM> and <NUM> and/or edges of the substrate <NUM>. The substrate <NUM> may have a selected length and width, or diameter, to define its surface area. The substrate <NUM> may have at least one edge between the primary surfaces <NUM> and <NUM> of the substrate <NUM> defined by its length and width, or diameter. The substrate <NUM> may also have a selected thickness.

As used herein, a "selected depth," (e.g., selected depth <NUM>) "depth of compression" and "DOC" are used interchangeably to define the depth at which the stress in the substrate <NUM>, as described herein, changes from compressive to tensile. DOC may be measured by a surface stress meter, such as an FSM-<NUM>, or a scattered light polariscope (SCALP) depending on the ion exchange treatment. Where the stress in a substrate <NUM> having a glass or a glass-ceramic composition is generated by exchanging potassium ions into the glass substrate, a surface stress meter is used to measure DOC. Where the stress is generated by exchanging sodium ions into the glass article, SCALP is used to measure DOC. Where the stress in the substrate <NUM> having a glass or glass-ceramic composition is generated by exchanging both potassium and sodium ions into the glass, the DOC is measured by SCALP, since it is believed the exchange depth of sodium indicates the DOC and the exchange depth of potassium ions indicates a change in the magnitude of the compressive stress (but not the change in stress from compressive to tensile); the exchange depth of potassium ions in such glass substrates is measured by a surface stress meter. As also used herein, the "maximum compressive stress" is defined as the maximum compressive stress within the compressive stress region <NUM> in the substrate <NUM>. In some examples, the maximum compressive stress is obtained at or in close proximity to the one or more primary surfaces <NUM> and <NUM> defining the compressive stress region <NUM>. In other examples, the maximum compressive stress is obtained between the one or more primary surfaces <NUM> and <NUM> and the selected depth <NUM> of the compressive stress region <NUM>.

In some examples of the article <NUM>, as depicted in exemplary form in <FIG>, the substrate <NUM> is selected from a chemically strengthened alumino-boro-silicate glass or glass-ceramic. For example, the substrate <NUM> can be selected from chemically strengthened alumino-boro-silicate glass or glass-ceramic having a compressive stress region <NUM> extending to a first selected depth <NUM> of greater than <NUM>, with a maximum compressive stress of greater than <NUM> MPa. In further examples, the substrate <NUM> is selected from a chemically strengthened alumino-boro-silicate glass or glass-ceramic having a compressive stress region <NUM> extending to a first selected depth <NUM> of greater than <NUM>, with a maximum compressive stress of greater than <NUM> MPa. The substrate <NUM> of the article <NUM> may also include one or more compressive stress regions <NUM> that extend from one or more of the primary surfaces <NUM> and <NUM> to a selected depth <NUM> (or depths) having a maximum compressive stress of greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, greater than <NUM> MPa, and all maximum compressive stress levels between these values. In some examples, the maximum compressive stress is <NUM> MPa or lower. In addition, the depth of compression (DOC) or first selected depth <NUM> can be set at <NUM> or greater, <NUM> or greater, <NUM> or greater, <NUM> or greater, <NUM> or greater, <NUM> or greater, and to even higher depths, depending on the thickness of the substrate <NUM> and the processing conditions associated with generating the compressive stress region <NUM>. In some examples, the DOC is less than or equal to <NUM> times the thickness (t) of the substrate <NUM>, for example, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, <NUM>*t, and all values therebetween.

As will be explained in greater detail below, the article <NUM> is formed from an as-batched composition and is cast in a glass state. The article <NUM> may later be annealed and/or thermally processed (e.g., heat treated) to form a glass-ceramic state having a plurality of ceramic or crystalline particles. It will be understood that depending on the casting technique employed, the article <NUM> may readily crystallize and become a glass-ceramic without additional heat treatment (e.g., essentially be cast into the glass-ceramic state). In examples where a post-forming thermal processing is employed, a portion, a majority, substantially all or all of the article <NUM> may be converted from the glass state to the glass-ceramic state. As such, although compositions of the article <NUM> may be described in connection with the glass state and/or the glass-ceramic state, the bulk composition of the article <NUM> may remain substantially unaltered when converted between the glass and glass-ceramic states, despite localized portions of the article <NUM> having a different composition (i.e., owing to the formation of the ceramic or crystalline precipitates). Further, it will be understood that while the compositions are described in terms of an as-batched state, one having ordinary skill in the art will recognize which constituents of the article <NUM> may volatize in the melting process (i.e., and therefore be less present in the article <NUM> relative to the as-batched composition) and others which will not.

The article <NUM> includes Al<NUM>O<NUM>, SiO<NUM>, B<NUM>O<NUM>, WO<NUM> and/or MoO<NUM>, Fe<NUM>O<NUM> and/or MnO<NUM>, and may include R<NUM>O where R<NUM>O is one or more of Li<NUM>O, Na<NUM>O, K<NUM>O, Rb<NUM>O and Cs<NUM>O. The article <NUM> may also include RO where RO is one or more of MgO, CaO, SrO, BaO and ZnO and/or any number of dopants (e.g., SnO<NUM>, F, P<NUM>O<NUM>, etc.). Unless otherwise noted, glass compositions correspond to as-batched mole percentage (mol%) in a crucible for melting.

The article <NUM> comprises from <NUM> mol% to <NUM> mol% SiO<NUM>, for example from <NUM> mol% to <NUM> mol% SiO<NUM>, or from <NUM> mol% to <NUM> mol% SiO<NUM>, or from <NUM> mol% to <NUM> mol% SiO<NUM> or from <NUM> mol% to <NUM> mol% SiO<NUM>. For example, the article <NUM> may have <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol% or <NUM> mol% SiO<NUM>.

The article <NUM> includes from <NUM> mol% to <NUM> mol% Al<NUM>O<NUM>, for example from <NUM> mol% to <NUM> mol% Al<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% Al<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% Al<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% Al<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% Al<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% Al<NUM>O<NUM>. For example, the article <NUM> may have <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, or <NUM> mol% Al<NUM>O<NUM>.

The article <NUM> includes WO<NUM> and/or MoOs. The combined amount of WO<NUM> and MoOs is referred to herein as "WO<NUM> plus MoO<NUM>" where it is understood that "WO<NUM> plus MoOs" refers to WO<NUM> alone, MoOs alone, or a combination of WO<NUM> and MoOs. WO<NUM> plus MoOs is from <NUM> mol% to <NUM> mol%, for example from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol to <NUM> mol%. With respect to WO<NUM>, the article <NUM> may have from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%. For example, the article may have <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol% WO<NUM>. With respect to MoOs, the article <NUM> may have from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%. For example, the article may have <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, or <NUM> mol% MoOs.

The article <NUM> includes from <NUM> mol% to <NUM> mol% B<NUM>O<NUM>, for example from <NUM> mol% to <NUM> mol% of B<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% B<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% B<NUM>O<NUM>. For example, the article <NUM> may have <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, or <NUM> mol% B<NUM>O<NUM>.

The article <NUM> can include at least one alkali metal oxide. The alkali metal oxide is represented by the chemical formula R<NUM>O where R<NUM>O is one or more of Li<NUM>O, Na<NUM>O, K<NUM>O, Rb<NUM>O, Cs<NUM>O and/or combinations thereof. The article <NUM> comprises R<NUM>O from <NUM> mol% to <NUM> mol%, for example from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol% R<NUM>O. For example, the article <NUM> may have <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, or <NUM> mol% R<NUM>O.

The article <NUM> has an alkali content such that R<NUM>O minus Al<NUM>O<NUM> (i.e., the difference between the amount of R<NUM>O and Al<NUM>O<NUM>) ranges from -<NUM> mol% to +<NUM> mol%, for example from -<NUM> mol% to +<NUM> mol%, or from -<NUM> mol% to +<NUM> mol%, or from <NUM> mol% to + <NUM> mol%, or from +<NUM> mol% to +<NUM> mol%, or from +<NUM> mol% to +<NUM> mol%, or from +<NUM> mol% to +<NUM> mol%, or from +<NUM> mol% to +<NUM> mol%. The difference in R<NUM>O and Al<NUM>O<NUM> specified herein influences the availability of excess alkali cations to interact with tungsten oxide, thereby modulating or otherwise controlling the formation of alkali tungsten bronzes, e.g. non-stoichiometric tungsten sub-oxides (MxWO<NUM> crystals with x > <NUM>) and stoichiometric alkali tungstates (e.g., Na<NUM>WO<NUM>). Without being bound by theory, the excess alkali in the glass of article <NUM> enables more of it intercalate into the tungsten crystal to form higher dopant concentration bronze crystals, which can produce further absorbance changes upon various levels of crystallization (e.g., through post-melt heat treatments). Put another way, the excess alkali levels can allow greater variations in the MxWO<NUM> crystal stoichiometry, resulting in more significant shifts in band gap energy which is manifested in changes in absorbance.

The article includes Fe<NUM>O<NUM> and/or MnO<NUM>. The combined amount of Fe<NUM>O<NUM> and MnO<NUM> is referred to herein as "Fe<NUM>O<NUM> plus MnO<NUM>" where it is understood that "Fe<NUM>O<NUM> plus MnO<NUM>" refers to Fe<NUM>O<NUM> alone, MnO<NUM> alone, or a combination of Fe<NUM>O<NUM> and MnO<NUM>. Fe<NUM>O<NUM> plus MnO<NUM> is from <NUM> mol% to <NUM> mol%, for example from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%. With respect to Fe<NUM>O<NUM>, the article <NUM> may have from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%. For example, the article may have <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, or <NUM> mol% Fe<NUM>O<NUM>. With respect to MnO<NUM>, the article <NUM> may have from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%. For example, the article may have <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, or <NUM> mol% MnO<NUM>.

The article <NUM> may also include at least one alkaline earth metal oxide and/or ZnO. The alkaline earth metal oxide may be represented by the chemical formula RO where RO is one or more of MgO, CaO, SrO and BaO. RO may also include ZnO. The article <NUM> may include RO from <NUM> mol% to <NUM> mol% RO, or from <NUM> mol% to <NUM> mol% RO, or from <NUM> mol% to <NUM> mol% RO, or from <NUM> mol% to <NUM> mol% RO, or from <NUM> mol% to <NUM> mol% RO, or from <NUM> mol% to <NUM> mol% RO, or from <NUM> mol% to <NUM> mol% RO. According to various examples, the amount of R<NUM>O may be greater than the amount of RO and/or ZnO. Further, embodiments of the article <NUM> may be substantially free of RO and/or ZnO.

The article <NUM> may also include SnO<NUM>, from <NUM> mol% to <NUM> mol% SnO<NUM>, or from <NUM> mol% to <NUM> mol% SnO<NUM>, or from <NUM> mol% to <NUM> mol% SnO<NUM>, or from <NUM> mol% to <NUM> mol% SnO<NUM>. For example, the article <NUM> can include <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, <NUM> mol% SnO<NUM>, and <NUM> mol% SnO<NUM>. Without being bound by theory, the tin oxide levels in article <NUM> and the compositions of the present disclosure can play an important role in the partial reduction of the tungsten bronze crystal (e.g., with some degree of synergy with the excess alkali content in the compositions), which is a component that may greatly facilitate obtaining further stoichiometry variations (i.e., larger x values in the MxWO<NUM> non-stoichiometric crystals, which require more W<NUM>+ to be reduced to W<NUM>+).

According to various examples, the article <NUM> can be doped with P (in the form of P<NUM>O<NUM>) and/or F (in the form of F- ions). For example, the article <NUM> can include from <NUM> mol% to <NUM> mol% P<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% P<NUM>O<NUM>, or from <NUM> mol% to <NUM> mol% P<NUM>O<NUM>. The article <NUM> can also include F from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%. Without being bound by theory, the articles <NUM> containing P<NUM>O<NUM> and/or F can be 'softer' from a viscosity standpoint as these dopants can be added at the expense of some amount of SiO<NUM>. Further, such 'softer' compositions can enable increased alkali metal oxides partitioning into the W-containing crystals as there is less SiO<NUM> to compete with the alkali metal oxides. Further, the increased viscosity curve associated with these 'softer' compositions can also influence the rate of diffusion of the alkali metal oxides into the tungsten crystals. With increased alkali metal oxide partitioning into the W-containing crystals, additional absorbance-changing effects can be obtained with one composition through varying heat treatments.

In various examples, the article <NUM> is substantially free of Cd and Se. Unless otherwise noted herein, the term "substantially free" means that the specified element or constituent is not intentionally included in the article <NUM> and any measurable amounts that are present in the article <NUM> are present at < <NUM> ppm. In some embodiments, the articles <NUM> can be substantially free of Cd, Se and/or any other element subject to regulation under RCRA.

According to various examples, the article <NUM> can further include at least one dopant selected from the group consisting of H, S, Cl, Ti, V, Cr, Co, Ni, Cu, Ga, Se, Br, Zr, Nb, Ru, Rh, Pd, Ag, Cd, In, Sb, Te, I, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ta, Os, Ir, Pt, Au, Ti, Pb, Bi and U to alter the ultraviolet, visual, color and/or near-infrared absorbance. The dopants may have concentration within the glass composition of from <NUM> mol% to <NUM> mol%, from <NUM> mol% to <NUM> mol%, or from <NUM> mol% to <NUM> mol%. For example, the article <NUM> may contain any one or more of the foregoing dopants at a concentration of <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, <NUM> mol%, and <NUM> mol%.

Tables 1A, 1B and 1C provide exemplary composition ranges of the article <NUM> in an as-batched mol%.

Formation in conventional tungsten- or mixed tungsten molybdenum-containing alkali glasses has been hampered by the separation of the melt constituents during the melting process. The separation of the glass constituents during the melting process resulted in a perceived solubility limit of alkali tungstate within the molten glass, and therefore of articles cast from such melts. Conventionally, when a tungsten, molybdenum, or mixed tungsten-molybdenum melt was even slightly peralkaline (e.g., R<NUM>O minus Al<NUM>O<NUM> = <NUM> mol% or greater), the melted borosilicate glass formed both a glass and a dense liquid second phase. While the concentration of the alkali tungstate second phase could be minimized by thorough mixing, melting at a high temperature, and employing a small batch size (~ <NUM>), it could not be fully eliminated leading to formation of a deleterious second crystalline phase. It is believed that the formation of this alkali tungstate phase occurs in the initial stages of the melt, where tungsten oxide and the optional molybdenum oxide reacts with "free" or "unbound" alkali carbonates. Due to the high density of alkali tungstate and alkali molybdate relative to the borosilicate glass that is formed, it rapidly segregates and/or stratifies, pooling at the bottom of the crucible and does not rapidly solubilize in the glass due to the significant difference in density. As the R<NUM>O constituents may provide beneficial properties to the glass composition, simply decreasing the presence of the R<NUM>O constituents within the melt may not be desirable. As the tungsten and/or molybdenum segregates, it is difficult to saturate the glass with it, and accordingly, it is difficult to get it to crystallize from the glass and form the precipitates as described herein.

It has been discovered that a homogenous single phase W-, single phase Mo- or mixed W- and Mo-containing peralkaline melt may be obtained through the use of "bound" alkalis. For purposes of this disclosure, "bound" alkalis are alkali elements which are bonded to oxygen ions which are bound to aluminum, boron, and/or silicon atoms, while "free" or "unbound" alkalis are alkali carbonates, nitrates, or sulfates, which are not bound to an oxygen ion already bound to silicon, boron, or aluminum atoms. Exemplary bound alkalis may include feldspar, nepheline, borax, spodumene, other sodium or potassium feldspars, alkali-aluminum-silicates and/or other oxide compositions containing an alkali and one or more aluminum and/or silicon atoms. By introducing the alkali in the bound form, the alkalis may not react with the W and/or Mo present in the melt to form the dense alkali tungstate and/or alkali molybdate liquid. Moreover, this change in batch material may allow the melting of strongly peralkaline compositions (e.g., R<NUM>O-Al<NUM>O<NUM> = <NUM> mol% or more) without the formation of an alkali tungstate and/or alkali molybdate second phase. This has also allowed the melt temperature and mixing method to be varied and still produce a single-phase homogenous glass. It will be understood that as the alkali tungstate phase and the borosilicate glass are not completely immiscible, prolonged stirring may also allow mixing of the two phases to cast a single phase article.

Once the glass melt is cast and solidified into the glass state article, the article <NUM> may be annealed, heat treated or otherwise thermally processed to form or modify a crystalline phase within the article <NUM>. Accordingly, the article <NUM> may be transformed from the glass state to the glass-ceramic state. The crystalline phase of the glass-ceramic state may take a variety of morphologies. According to various examples, the crystalline phase is formed as a plurality of precipitates, such as homogenously distributed precipitates, within the heat treated region of the article <NUM>. As such, the precipitates may have a generally crystalline structure. The glass-ceramic state may include two or more crystalline phases.

As used herein, "a crystalline phase" refers to an inorganic material within the articles of the disclosure that is a solid composed of atoms, ions or molecules arranged in a pattern that is periodic in three dimensions. Further, "a crystalline phase" as referenced in this disclosure, unless expressly noted otherwise, is determined to be present using the following method. First, powder x-ray diffraction ("XRD") is employed to detect the presence of crystalline precipitates. Second, Raman spectroscopy ("Raman") is employed to detect the presence of crystalline precipitates in the event that XRD is unsuccessful (e.g., due to size, quantity and/or chemistry of the precipitates). Optionally, transmission electron microscopy ("TEM") is employed to visually confirm or otherwise substantiate the determination of crystalline precipitates obtained through the XRD and/or Raman techniques. In certain circumstances, the quantity and/or size of the precipitates may be low enough that visual confirmation of the precipitates proves particularly difficult. As such, the larger sample size of XRD and Raman may be advantageous in sampling a greater quantity of material to determine the presence of the precipitates.

The crystalline precipitates may have a generally rod-like or needle-like morphology. The precipitates may have a longest length dimension of from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>. The size of the precipitates may be measured using Electron Microscopy. For purposes of this disclosure, the term "Electron Microscopy" means visually measuring the longest length of the precipitates first by using a scanning electron microscope, and if unable to resolve the precipitates, next using a transmission electron microscope. As the crystalline precipitates may generally have a rod-like or needle-like morphology, the precipitates may have a width of from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>. It will be understood that the size and/or morphology of the precipitates may be uniform, substantially uniform or may vary.

The relatively small size of the precipitates may be advantageous in reducing the amount of light scattered by the precipitates leading to high optical clarity of the article <NUM> when in the glass-ceramic state. As will be explained in greater detail below, the size and/or quantity of the precipitates may be varied across the article <NUM> such that different portions of the article <NUM> may have different optical properties. For example, portions of the article <NUM> where the precipitates are present may lead to changes in the absorbance, color, reflectance, transmission of light, and/or refractive index, as compared to portions of the article <NUM> where different precipitates (e.g., size and/or quantity) and/or no precipitates are present.

The precipitates may be composed of tungsten oxide, molybdenum oxide or tungsten oxide and molybdenum oxide plus iron and/or manganese. The crystalline phase includes an oxide, from <NUM> mol% to <NUM> mol% of the crystalline phase, of at least one of: (i) W + Fe and/or Mn; (ii) Mo + Fe and/or Mn; (iii) Mo + W + Fe and/or Mn; and (iv) any of (i)-(iii) and an alkali metal cation. Without being bound by theory, it is believed that during thermal processing (e.g., heat treating) of the article <NUM>, the tungsten and/or the molybdenum cations, along with the iron and/or manganese cations, can agglomerate to form crystalline precipitates thereby transforming the glass state into the glass-ceramic state. The molybdenum and/or tungsten, along with the iron and/or manganese, present in the precipitates may be reduced, or partially reduced. For example, the molybdenum and/or tungsten within the precipitates may have an oxidation state of between <NUM> and +<NUM>, or from +<NUM> and +<NUM>, or from +<NUM> and +<NUM>. According to various examples, the molybdenum and/or tungsten may have a +<NUM> oxidation state. For example, the precipitates formed by these glass-ceramics may have the general chemical structure of WO<NUM> and/or MoOs. Other precipitates formed by these glass-ceramics may be known as non-stoichiometric tungsten suboxides, non-stoichiometric molybdenum suboxides, "molybdenum bronzes" and/or "tungsten bronzes. " One or more of the above-noted alkali metals, Fe and/or Mn, and/or other dopants may be present within the precipitates. Tungsten, molybdenum and/or mixed tungsten molybdenum bronzes are a group of non-stoichiometric tungsten and/or molybdenum sub-oxides that takes the general chemical form of MxWO<NUM> or MxMoO<NUM>, where M = Fe, Mn, H, Li, Na, K, Rb, Cs, Ca, Sr, Ba, Zn, Ag, Au, Cu, Sn, Cd, In, Tl, Pb, Bi, Th, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, and U, and where <NUM> < x < <NUM>. The structures MxWO<NUM> and MxMoO<NUM> are considered to be a solid state defect structure in which holes (vacancies and/or interstices) in a reduced WO<NUM>, MoOs, WO<NUM> and/or MoO<NUM> network are randomly occupied by M atoms, which are dissociated into M+ or M<NUM>+ cations and free electrons. Depending on the concentration of "M," the material properties can range from metallic to semi-conducting, thereby allowing a variety of optical absorption and electronic properties to be tuned. Further, the structure of these bronzes is considered to be a solid state defect structure in which M cations intercalate into holes or channels of the oxide host and dissociate into M<NUM>+ or M<NUM>+cations and free electrons. In turn, as x is varied, these materials can exist as a broad sequence of solid phases with definite and wide ranges of homogeneity. As another example, the crystalline precipitates of the article <NUM> can comprise an oxide of at least one of the chemical form MWO<NUM> and/or MMoO<NUM>, in which M is Fe<NUM>+ or Mn<NUM>+. These crystalline phases known as tungstates (or molybdates) derive their name from the simplest tungsten and molybdenum anions WO<NUM><NUM>- and MoO<NUM><NUM>-, which can be charged stabilized <NUM>+ cations such as Fe<NUM>+ and/or Mn<NUM>+ to form stable crystalline species. Naturally occurring iron and manganese tungstates are known colloquially as the mineral Ferberite (FeWO<NUM>) and Hubnerite (MnWO<NUM>). There are also naturally occurring iron and manganese molybdates.

A portion, a majority, substantially all or all of the article <NUM> may be thermally processed to form the precipitates. Thermal processing techniques may include, but are not limited to, a furnace (e.g., a heat treating furnace), a laser and/or other techniques of locally and/or bulk heating of the article <NUM>. While undergoing thermal processing, the crystalline precipitates internally nucleate within the article <NUM> in a homogenous manner where the article <NUM> is thermally processed to form the glass-ceramic state. As such, in some examples, the article <NUM> may include both glass and glass-ceramic portions. In examples where the article <NUM> is thermally processed in bulk (e.g., the whole article <NUM> is placed in a furnace), the precipitates may homogenously form throughout the article <NUM>. In other words, the precipitates may exist from a surface of the article <NUM> throughout the bulk of the article <NUM> (i.e., greater than <NUM> from the surface). In examples where the article <NUM> is thermally processed locally (e.g., via a laser), the precipitates may only be present where the thermal processing reaches a sufficient temperature (e.g., at the surface and into the bulk of the article <NUM> proximate the heat source). It will be understood that the article <NUM> may undergo more than one thermal processing to produce the precipitates. Additionally or alternatively, thermal processing may be utilized to remove and/or alter precipitates which have already been formed (e.g., as a result of previous thermal processing). For example, thermal processing may result in the decomposition of precipitates.

According to various examples, the article <NUM> may be black in color. For purposes of this disclosure, the term "black" or "pure black" means a material which is capable of exhibiting an absorbance of at least <NUM> OD/mm across the visible spectrum (i.e., <NUM> to <NUM>). The tungsten and molybdenum bronzes, as containing iron and/or manganese, of the disclosure can also exhibit strong UV and VIS absorption. Without being bound by theory, the mechanistic origin of the optical absorbance of examples of the glass-ceramics of the disclosure can arise due to the formation of solid solutions of various crystalline species from the wolframite solid solution family. Wolframite is an iron manganese tungstate solid solution mineral of the form (Fe,Mn)WO<NUM> that is the intermediate between the pure iron end-member Ferberite (FeWO<NUM>) and the pure manganese end member Hübernerite (MnWO<NUM>).

The crystallites in the pure black absorptive glass-ceramics of the disclosure comprise oxides of iron plus tungsten, iron plus molybdenum, iron plus tungsten plus molybdenum (in the case of a mixed tungsten/molybdenum glass ceramic), or any of the aforementioned combinations plus at least one of the following dopants that could either reside in the glass or intercalate into the crystal: H, S, Cl, Ti, V, Cr, Co, Ni, Cu, Ga, Se, Br, Zr, Nb, Ru, Rh, Pd, Ag, Cd, In, Sb, Te, I, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ta, Os, Ir, Pt, Au, Tl, Pb, Bi, and U. In some embodiments of these glass-ceramics, the at least one dopant is present in the glass-ceramic from <NUM> mol% to <NUM> mol%. Similarly, the crystallites in the glass-ceramics of the disclosure that give rise to optical absorbance profiles analogous to cadmium and selenium-containing filter glasses (e.g., for optical filter applications) comprise oxides of manganese plus tungsten, manganese plus molybdenum, manganese plus tungsten plus molybdenum (in the case of a mixed tungsten/molybdenum glass ceramic), or any of the aforementioned combinations plus at least one of the following dopants that could either reside in the glass or intercalate into the crystal: H, S, Cl, Ti, V, Cr, Co, Ni, Cu, Ga, Se, Br, Zr, Nb, Ru, Rh, Pd, Ag, Cd, In, Sb, Te, I, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ta, Os, Ir, Pt, Au, Tl, Pb, Bi, and U. In some embodiments of these glass-ceramics, the at least one dopant is present in the glass-ceramic from <NUM> mol% to <NUM> mol%. Further, the amounts of these dopant(s) can be used to further modify the optical absorbance of the glass-ceramic (e.g., to obtain a sharp cutoff wavelength), e.g., as necessary based on the intended optics-related application for the article employing the glass-ceramic.

The thermal processing of the article <NUM> to develop the precipitates, generate the black color and/or generate the absorbance profile suitable for an optics-related application (e.g., with a sharp cutoff wavelength) may be accomplished in a single step or through multiple steps. For example, the generation of a pure black color or a particular optical absorbance profile exhibited by the article <NUM> (e.g., which starts with the formation of a WO<NUM> and/or MoOs precipitates followed by the partial reduction of that crystallite with the simultaneous intercalation of a dopant species (e.g., alkali metal cations into the crystal)) can be completed in a single heat treatment immediately after the article <NUM> is formed, or at a later point. For example, the article <NUM> may be cast and then processed into a final form (e.g., lens blanks or other optical or aesthetic elements) and then annealed at a temperature just below where color is generated (e.g., intercalation of the alkali metal ions into the precipitates). This annealing may start the clustering of WO<NUM> and/or MoOs, and then a secondary thermal processing may occur at an elevated temperature to allow further crystallization and the partial reduction of the WO<NUM> and/or MoOs crystals and intercalation of alkali metal ions and/or other species to generate color. It may also enable the chemical formation of iron- and/or manganese-doped tungstates, molybdates, and/or mixed W+Mo 'tungsto-molybdates'.

The thermal processing of the article <NUM>, which generates the precipitates and/or intercalates the dopants into the precipitates, may occur under a variety of times and temperatures. It will be understood that thermal processing of the article <NUM> is carried out in air unless otherwise noted. In examples where the article <NUM> is thermally processed in a furnace, the article <NUM> may be placed in the furnace at room temperature with a controlled ramping in temperature and/or may be "plunged" into a furnace already at an elevated temperature. The thermal processing may occur at a temperature of from <NUM>°C to <NUM>°C. For example, the secondary thermal processing (e.g., post-annealing) may take place at a temperature of <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM> C, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>, or <NUM>. In preferred embodiments, the secondary thermal processing can take place from <NUM> to <NUM>, or from <NUM> to <NUM>, which is substantially lower in temperature than the thermal processing employed in conventional glass-ceramic compositions (e.g., containing Fe and/or Mn dopants but no molybdenum or tungsten) that may be capable of achieving a pure black color.

The secondary thermal processing (e.g., post-annealing) may be carried out for a time period of from <NUM> second to <NUM> hours. For example, the thermal processing may be carried out for <NUM> second, or <NUM> seconds, or <NUM> seconds, or <NUM> minute, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes, or <NUM> minutes. It will be understood that thermal processing may be carried out for significantly longer times upwards of <NUM> hours or more, <NUM> hours or more, <NUM> hours or more, <NUM> hours or more, <NUM> hours or more, <NUM> hours or more, <NUM> hours or more, <NUM> hours or more, <NUM> hours or more or <NUM> hours or more. In preferred embodiments, the secondary thermal processing can be conducted from <NUM> minutes to <NUM> minutes, or from <NUM> minutes to <NUM> minutes, which is a substantially shorter duration than the duration of thermal processing employed in conventional glass-ceramic compositions that may be capable of achieving a pure black color.

In some examples, the article <NUM> may then be cooled to a lower temperature at a rate of <NUM>. <NUM> per minute, or <NUM> per minute, or <NUM> per minute, or <NUM> per minute, or <NUM> per minute, or <NUM> per minute, or <NUM> per minute, or <NUM> per minute, or <NUM> per minute, or <NUM> per minute or <NUM> per minute. The lower temperature may be from room temperature (e.g., <NUM>) to <NUM>. For example, the lower temperature may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. It will be understood that the article <NUM> may undergo a multistage thermal processing using one or more of the above noted times, temperatures and cooling rates.

As explained above, additionally or alternatively to the use of a furnace, the article <NUM> may be thermally processed through the use of a laser and/or other localized heat source. Such an example may be advantageous in producing a localized darker or lighter region within the glass-ceramic. The laser and/or localized heat source may supply sufficient thermal energy to create the precipitates and/or intercalate one or more alkali metal ions into the precipitates to generate localized color and/or differences in absorbance. The laser and/or other heat source may be rastered or guided across the article <NUM> to preferentially create varied optical properties across the article <NUM>. The intensity and/or speed of the laser and/or localized heat source may be adjusted as it is moved across the article <NUM> such that various portions of the article <NUM> exhibit different levels of dark shading. Such features may be advantageous in creating indicia, symbols, text, numbers and/or pictures in the article <NUM>.

The article <NUM> may exhibit an absorbance over certain wavelength bands of electromagnetic radiation. The absorbance may be expressed in terms of optical density per millimeter (OD/mm). As understood by those in the art, optical density is the log of the ratio of light intensity exiting the article <NUM> to light intensity entering the article <NUM>. Absorbance data may be collected using a UV/VIS spectrophotometer in conformance with the measurement rules according to ISO <NUM>. Over an ultraviolet (UV) wavelength range of from <NUM> to <NUM>, the article <NUM> may have an average absorbance from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm. For example, the article <NUM> may have an average absorbance over a wavelength of from <NUM> to <NUM> of <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater, or <NUM> OD/mm or greater.

Over a visible wavelength range of from <NUM> to <NUM>, the article <NUM> may have an average absorbance of <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm. For example, the article <NUM> may have an average absorbance over a wavelength of from <NUM> to <NUM> of at least <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, or <NUM> OD/mm.

Over a wavelength range of from <NUM> to <NUM>, the article <NUM> may have an average absorbance of <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm, or from <NUM> OD/mm to <NUM> OD/mm. For example, over a wavelength range of from <NUM> to <NUM>, the article <NUM> may have an absorbance of <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, <NUM> OD/mm, or <NUM> OD/mm.

The article <NUM> may exhibit differing transmittances over different wavelength bands of electromagnetic radiation. The transmittance may be expressed in a percent transmittance. Transmittance data may be collected using a UV/VIS spectrophotometer on a sample having a <NUM> thickness in conformance with the measurement rules according to ISO <NUM>, unless otherwise noted in the disclosure. Over a UV wavelength range of from <NUM> to <NUM>, the article <NUM> may have transmittance of <NUM>% to <NUM>%, or from <NUM> to <NUM>%, or from <NUM>% to <NUM>%. For example, the article <NUM> may have a transmittance over a wavelength of from <NUM> to <NUM> of <NUM>%, or <NUM>%, or <NUM>%, or <NUM>%, or <NUM>%, or <NUM>%, or <NUM>%, or <NUM>%, or <NUM>% or <NUM>%.

The article <NUM> may have a transmittance over a visible wavelength range of from <NUM> to <NUM> of <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%. In some examples having a thickness of <NUM>, the article <NUM> exhibits an average transmittance of at least <NUM>%, at least <NUM>%, at least <NUM>%, or at least <NUM>%, within a wavelength range from <NUM> to <NUM>.

The article <NUM> may have a transmittance over an infrared (IR) or near-infrared (NIR) wavelength range of from <NUM> to <NUM> of <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%. According to some examples, the article <NUM> may exhibit a transmittance of at least <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% in the IR/NIR wavelength range from <NUM> to <NUM>. In some examples having a thickness of <NUM>, the article <NUM> exhibits an average transmittance of at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, or at least <NUM>%, within a wavelength range from <NUM> to <NUM>.

As disclosed above, glass-ceramic, according to some exemplary embodiments, has transmittance of about <NUM>%/mm or greater over at least one <NUM>-wide wavelength band of light in a range from about <NUM> to about <NUM>. However, in other embodiments, the glass-ceramics have lower transmittance, such as those that are opaque. According to at least some such embodiments, the glass-ceramics strongly absorb, but do not scatter, light and have low haze. According to various such embodiments, the glass-ceramics have an average absorbance of at least <NUM> OD/mm for at least some light with <NUM> to <NUM> wavelengths (e.g., ><NUM>%), or at least <NUM> OD/mm for light over the same wavelengths. These glass-ceramics can also exhibit a haze of less than <NUM>%. According to various embodiments, the glass-ceramics of the disclosure have an average absorbance of at least <NUM> OD/mm for at least some of light with <NUM> to <NUM> wavelengths (e.g., ><NUM>%), or at least <NUM> OD/mm for light over the same wavelengths. The article <NUM>, according to these embodiments, can also exhibit a haze of less than <NUM>%. According to various such embodiments, the glass-ceramics also exhibit an absorbance of at least <NUM> OD/mm for at least some of light with <NUM> to <NUM> wavelengths (e.g., > <NUM>%) and some light with <NUM> to <NUM> wavelengths (e.g., > <NUM>%), respectively, or at least <NUM> OD/mm for some light over the same wavelengths. It should also be understood that optical density is calculated from measurements of optical absorbance, which is made with a spectrophotometer; and haze is measured by a haze meter wide-angle scattering test.

The article <NUM> may also exhibit a scattering of from <NUM>% to <NUM>% over a visible wavelength band of <NUM> to <NUM> at a thickness of <NUM>. For example, the article <NUM> may exhibit a scattering of <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less, <NUM>% or less or <NUM>% or less. Scattering data is collected in conformance with ISO <NUM> (<NUM>) Optics and Optical Instruments - Test methods for radiation scattered by optical components.

In some aspects of the disclosure, the article <NUM> may exhibit a sharp cutoff wavelength in a wavelength band from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>.

According to various examples, the article <NUM> may exhibit a low haze. For example, the article may exhibit a haze of <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less, or <NUM>% or less. The haze of the article is measured on a <NUM> thick sample and in accordance with the procedure outlined above in connection with haze measurement. According to various examples, the haze of the article may be lower than conventional glass-ceramics, including conventional glass-ceramics capable of achieving a black hue. Further, the haze of the article may be due to the low quantity or absence of large crystallites (e.g., <<NUM>, or <<NUM>, or <<NUM>) which tend to scatter light.

Various examples of the present disclosure may offer a variety of properties and advantages. It will be understood that although certain properties and advantages may be disclosed in connection with certain compositions, various properties and advantages disclosed may equally be applicable to other compositions.

First, glass-ceramic compositions of the article <NUM> can be characterized as a pure black material at relatively low thicknesses (e.g., from <NUM> to <NUM>), which can be formed into a chemically strengthened, scratch-resistant sheet. Such sheets are suitable for use as components, including housings and enclosures, of portable computing devices.

Second, the pure black glass-ceramic compositions of the article <NUM> can be produced with low temperature (e.g., from <NUM> to <NUM>) and low duration (e.g., from <NUM> minutes to <NUM> minutes) heat treatment cycles, which are significantly lower in temperature and shorter in duration than the heat treatment steps to produce comparable black colors in conventional glass-ceramic compositions. Accordingly, the glass-ceramic compositions of the disclosure can be produced with significantly lower production costs than conventional glass-ceramics with similar properties. Another benefit of the low temperature heat treatment cycles of the glass-ceramic compositions of the disclosure is that they are relatively close in temperature to the typical annealing cycles that preceded these heat treatment cycles. As such, the glass-ceramic compositions of the disclosure can be heat-treated with a low risk of sheet warp or surface deformation during the heat treatment cycle employed to develop the crystalline precipitates in the glass. In addition, some of the glass-ceramic compositions of the disclosure for use in article <NUM> can be tailored to spontaneously crystallize upon melting and annealing to form a pure black without the need for an additional heat treatment step.

Third, the compositions of the article <NUM> can have a sufficiently high liquidus viscosity such that the article <NUM> may be capable of fusion forming or three-dimensional (3D) forming processes. With respect to ion-exchanging, ion-exchanging may provide a compressive stress at the selected depth <NUM> which may increase the durability and/or scratch resistance of the article <NUM>. Further, the glass-ceramic compositions of the disclosure are not susceptible to the color alteration- or haze-related problems associated with 3D forming processes employed with other conventional glass-ceramic compositions. Notably, embodiments of the glass-ceramics of the disclosure do not bleach upon re-heating (after the heat treatment cycle); consequently, the glass-ceramics of the disclosure do not require post-processing upon being formed into a desired shape with a 3D forming process.

Fourth, the Fe-containing glass-ceramic compositions of the disclosure can be characterized with a low propensity for radiation trapping during melting (e.g., IR-influenced radiation trapping). In materials susceptible to radiation trapping, viscosity levels can significantly fluctuate during processing leading to process instabilities, particularly for fusion draw processing of the material in sheet form. As such, these glass-ceramic compositions are particularly suitable for conventional melting and fusion draw processing, particularly as compared to other conventional glass-ceramic compositions without tungsten and/or molybdenum oxides.

Fifth, Mn-containing glass-ceramic compositions of the disclosure, and the articles containing them, offer various advantages over conventional glass, glass-ceramic and ceramic materials employed in optics-related applications, including advantages over CdSe glasses. As noted earlier, examples of the glass-ceramic compositions of the disclosure are substantially free of Cd and Se, while offering sharp, visible extinctions that are analogous to orange-colored, conventional CdSe optical filter glasses. Further, the glass-ceramic materials of the disclosure are formulated with lower cost materials in comparison to conventional alternatives to CdSe glass that employ indium, gallium and/or other high-cost metals and constituents, some of which are highly regulated under RCRA. In addition, these glass-ceramic materials can be produced with conventional melt quench processes, unlike other conventional CdSe glass alternatives, such as indium and gallium-containing semiconductor-doped glasses that require additional semiconductor synthesis and milling steps.

Sixth, the Mn-containing glass-ceramic material can be characterized by a cutoff wavelength that is tunable through selection of heat treatment temperature and time conditions. The glass-ceramic materials of the disclosure also offer visible extinctions that are sharper in comparison to other non-cadmium-containing semiconductor-doped glasses, a conventional alternative to a CdSe glass.

The following examples represent certain non-limiting examples of the composition of the articles of the disclosure.

Referring now to Table <NUM>, a list of exemplary iron- and manganese-doped tungsten and molybdenum oxide glass-ceramics is provided. In particular, Exs. <NUM>-<NUM> to <NUM>-<NUM> are iron-doped, tungsten oxide glass-ceramic compositions, Exs. <NUM>-<NUM> to <NUM>-<NUM> are iron-doped molybdenum oxide glass-ceramic compositions, Exs. <NUM>-<NUM> to <NUM>-<NUM> are manganese-doped tungsten oxide glass-ceramic compositions, and Exs. <NUM>-<NUM> and <NUM>-<NUM> are manganese-doped molybdenum oxide glass-ceramic compositions, all suitable for use in an article (e.g., the article <NUM>) of the disclosure. Of the iron-doped compositions, Exs. <NUM>-<NUM> to <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> include fluorine, and Exs. <NUM>-<NUM>, to <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> are fluorine free. Of the manganese-doped compositions, Exs. <NUM>-<NUM> to <NUM>-<NUM> and <NUM>-<NUM> include fluorine, and Exs. <NUM>-<NUM> to <NUM>-<NUM> and Ex. <NUM>-<NUM> are fluorine free. Of the iron-doped compositions, Exs. <NUM>-<NUM>, <NUM> and <NUM> include phosphorous. Of the manganese-doped compositions, Exs. <NUM>-<NUM>, and <NUM> also include phosphorous. Further, all of these exemplary compositions are provided in as-batched mol%.

In this example, the compositions of Table <NUM> were prepared by weighing the batch constituents, mixing them by turbula or ball mill and melting for <NUM>-<NUM> hours at temperatures between <NUM> to <NUM> in Pt crucibles (silica, refractory or Pt/Rh crucibles can also be employed for the compositions of the disclosure). In some instances, a double melting approach was employed to improve melt homogeneity. The double melting involved pouring the molten glass into water, which rapidly quenched it resulting in the formation of small, fractured granules of the particular composition. The granules were then re-loaded into the crucible and melted again. Alternatively, these compositions could have been subjected to mechanical stirring to improve homogeneity with similar effect. The glasses were then cast onto a metal table to produce an `optical pour' or 'patty' of glass. Some melts were cast onto a steel table and then rolled into a sheet form using a steel roller. The glass was then annealed at temperatures between <NUM> to <NUM> for annealing times between <NUM> minutes and <NUM> minutes.

Some of the samples of the as-cast compositions of this example listed in Table <NUM> developed crystalline phases that gave rise to pure black or sharp cutoff wavelength characteristics upon the foregoing melting and the annealing steps, without the need for an additional, secondary heat treatment. The remaining compositions were subjected to a secondary heat treatment step that lasted for times between <NUM> minutes and <NUM> minutes at temperatures ranging from <NUM> to <NUM> in an ambient air electric oven.

In this example, a fluorine-containing, iron-doped tungsten oxide glass-ceramic was melted and annealed according to Ex. <NUM>-<NUM>, as outlined above in Table <NUM>. As shown in <FIG>, a photograph of the resulting glass-ceramic material (i.e., as an annealed optical pour) demonstrates that it has a pure black characteristic under ambient lighting, which is evident without any additional heat treatment.

After melting and annealing, the material from Example <NUM> was subjected to a heat treatment at <NUM> for <NUM> minutes, cooled to <NUM> at <NUM>/min, and then cooled at a furnace rate to room temperature in an ambient air electric oven. As shown in <FIG>, respectively, the resulting material was measured for optical absorbance and transmittance. In particular, <FIG> are plots of absorbance (OD/mm) and transmittance (%) as a function of wavelength (from <NUM> to <NUM>) at a <NUM> path length, respectively. Further, the optical absorbance data from <FIG> was evaluated to obtain average, minimum and maximum absorbance values for the material of this example at particular wavelength ranges (e.g., UV, VIS, and IR/NIR) regimes) and tabulated below in Table <NUM>.

Note that in some instances, the samples were so strong in absorbance at conventional thicknesses (e.g., <NUM> to <NUM>), they transmitted so little light that they were below the detector limit. Accordingly, for certain average and minimum values in Table <NUM> (and the subsequent tables in this disclosure), they are reported as absorbance greater than the specified value (e.g., ><NUM>) indicating that the sample absorbs at least the specified value in units of OD/mm.

In this example, a fluorine-free, iron-doped tungsten oxide glass-ceramic was melted and annealed according to Ex. <NUM>-<NUM>, as outlined above in Table <NUM>. After melting and annealing, the material from this example was subjected to a heat treatment at <NUM> for <NUM> minutes, cooled to <NUM> at <NUM>/min, and then cooled at a furnace rate to room temperature in an ambient air electric oven. As shown in <FIG>, respectively, the resulting material was measured for optical absorbance and transmittance. In particular, <FIG> are plots of absorbance (OD/mm) and transmittance (%) as a function of wavelength at a <NUM> path length, respectively. Further, the optical absorbance data from <FIG> was evaluated to obtain average, minimum and maximum absorbance values for the material of this example at particular wavelength ranges (e.g., UV, VIS, and IR/NIR) regimes) and tabulated below in Table <NUM>.

In this example, a fluorine-doped, iron-doped molybdenum oxide glass-ceramic was melted and annealed according to Ex. <NUM>-<NUM>, as outlined above in Table <NUM>. After melting and annealing, the material from this example was subjected to a heat treatment at <NUM> for <NUM> minutes, cooled to <NUM> at <NUM>/min, and then cooled at a furnace rate to room temperature in an ambient air electric oven. As shown in <FIG>, respectively, the resulting material was measured for optical absorbance and transmittance. In particular, <FIG> are plots of absorbance (OD/mm) and transmittance (%) as a function of wavelength at a <NUM> path length, respectively. Further, the optical absorbance data from <FIG> was evaluated to obtain average, minimum and maximum absorbance values for the material of this example at particular wavelength ranges (e.g., UV, VIS, and IR/NIR) regimes) and tabulated below in Table <NUM>.

In this example, the glass-ceramics of Examples <NUM>-<NUM> (Exs. <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>) are compared against a comparative glass-ceramic composition (Comp. <NUM>) doped with iron and titanium oxide, but lacks tungsten and molybdenum oxide. <NUM> has the following compositions (in as-batched mol%): <NUM>% SiO<NUM>; <NUM>% Al<NUM>O<NUM>; <NUM>% B<NUM>O<NUM>; <NUM>% Na<NUM>O; <NUM>% K<NUM>O; <NUM>% MgO; <NUM>% CaO; <NUM>% SnO<NUM>; <NUM>% ZrO<NUM>; <NUM>% TiO<NUM>; <NUM>% Fe<NUM>O<NUM>; and <NUM>% MnO. In particular, <FIG> are plots of absorbance (OD/mm) and transmittance (%) as a function of wavelength (from <NUM> to <NUM>) at a <NUM> path length, respectively, of these materials. In addition, <FIG> is a plot of absorbance (OD/mm) and transmittance (%) as a function of wavelength (from <NUM> to <NUM>) in the visible spectrum at a <NUM> path length, respectively, of these same materials. As is evident from the data in these figures, these samples exhibit comparable absorbance and transmittance characteristics across the UV, VIS and NIR spectra of the measurements. With regard to heat treatment, however, the samples of Examples <NUM>-<NUM> were heat treated at <NUM> for <NUM> minutes, <NUM> for <NUM> minutes and <NUM> for <NUM> minutes, respectively. In comparison, the comparative glass-ceramic required a heat treatment at <NUM> for two hours, followed by a further ramp to <NUM> with a four hour hold. As such, the samples of Examples <NUM>-<NUM> required <NUM>. 5x to <NUM>. 4x shorter heat treatment times at temperatures <NUM> to <NUM> lower than those employed with the comparative glass-ceramic.

Referring again to <FIG>, average transmittance (%) data for the <NUM> path length samples is tabulated below in Table <NUM> for the four samples of this example over the UV (<NUM> to <NUM>), VIS (<NUM> to <NUM>) and NIR (<NUM> to <NUM>; and <NUM> to <NUM>) wavelength regimes. As is evident from the data in Table <NUM>, these samples exhibit comparable transmittance characteristics across the UV, VIS and NIR spectra of the measurements.

In this example, manganese-doped tungsten oxide glass-ceramic compositions were melted and annealed according to Exs. <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>, as outlined above in Table <NUM>. After melting and annealing, the material from this example was subjected to a heat treatment at <NUM> for <NUM> minutes, cooled to <NUM> at <NUM>/min, and then cooled at a furnace rate to room temperature in an ambient air electric oven. These glass-ceramic samples were compared against a conventional CdSe glass (Comp. As shown in <FIG>, the samples of this example were measured for optical absorbance. In particular, <FIG> is a plot of absorbance (OD/mm) as a function of wavelength at a <NUM> path length. Further, the optical absorbance data from <FIG> was evaluated to obtain average, minimum and maximum absorbance values for the materials of this example (Exs. <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>) at particular wavelength ranges (e.g., UV, VIS, and IR/NIR) regimes) and tabulated below in Tables 7A-7C. As is evident from the data in <FIG> and Tables 7A-7C, the glass-ceramic compositions of this example derive their color from a manganese tungstate (MnWO<NUM>) and exhibit comparable color and absorbance characteristics as the RCRA-regulated comparative CdSe glass.

In this example, fluorine-free manganese-doped tungsten oxide glass-ceramic compositions were melted and annealed according to Exs. <NUM>-<NUM> and <NUM>-<NUM>, as outlined above in Table <NUM>. After melting and annealing, the material from this example was subjected to a heat treatment at <NUM> for <NUM> minutes, cooled to <NUM> at <NUM>/min, and then cooled at a furnace rate to room temperature in an ambient air electric oven. As shown in <FIG>, the samples of this example were measured for optical absorbance and transmittance. In particular, <FIG> are plots of absorbance (OD/mm) and transmittance (%) as a function of wavelength at a <NUM> path length. Further, the optical absorbance data from <FIG> was evaluated to obtain average, minimum and maximum absorbance values for the materials of this example (Exs. <NUM>-<NUM> and <NUM>-<NUM>) at particular wavelength ranges (e.g., UV, VIS, and IR/NIR) regimes) and tabulated below in Tables 8A and 8B. As is evident from the data in <FIG>, and Tables 8A and 8B, the glass-ceramic compositions of this example are well-suited for ophthalmic eyewear as they exhibit moderate to low visible transmittance and IR absorbance. Their absorbance is attributed to the formation of a manganese-tungstate-solid solution phase (i.e. Hübnerite).

In this example, iron-doped tungsten oxide glass-ceramic samples were prepared according to Table <NUM> (Exs. <NUM>-<NUM> to <NUM>-<NUM>) and subjected to powder x-ray diffraction (XRD) analysis, as depicted in <FIG>. Some of the samples were maintained in an annealed condition without a subsequent heat treatment: Exs. <NUM>-<NUM> and <NUM>-<NUM>, as shown in <FIG>. The remainder of the samples were subjected to a subsequent heat treatment: Ex. <NUM>-<NUM> at <NUM> for <NUM> minutes, as shown in <FIG>; Ex. <NUM>-<NUM> at <NUM> for <NUM> minutes, as shown in <FIG>; Ex. <NUM>-<NUM> at <NUM> for <NUM> minutes, as shown in <FIG>; Ex. <NUM>-<NUM> at <NUM> for <NUM> minutes, as shown in <FIG>; and Ex. <NUM>-<NUM> at <NUM> for <NUM> minutes, as shown in <FIG>. Each of the samples, Exs. <NUM>-<NUM> to <NUM>-<NUM>, were cooled in ambient air followed by the heat treatment at the specified temperature (e.g., Ex. <NUM>-<NUM>, <NUM> for <NUM> minutes, followed by cooling in ambient air). As is evident from the figures, all of the glass-ceramic compositions of the example exhibited an XRD signature for magnesium tungstate (MgWO<NUM>) as the primary crystalline phase. Since these compositions have only trace amounts of Mg and the d-spacing of magnesium tungstate and iron tungstate is very similar, it is believed that each of the XRD plots in <FIG> is indicative of the presence of iron tungstate, FeWO<NUM> (i.e., Ferberite).

In this example, manganese-doped tungsten oxide glass-ceramic samples were prepared according to Table <NUM> (Exs. <NUM>-<NUM> to <NUM>-<NUM>) and subjected to powder x-ray diffraction (XRD) analysis, as depicted in <FIG>. All of the samples were subjected to a subsequent heat treatment: Ex. <NUM>-<NUM> at <NUM> for <NUM> minutes, followed by cooling in ambient air, as shown in <FIG>; Ex. <NUM>-<NUM> at <NUM> for <NUM> minutes, followed by cooling in ambient air, as shown in <FIG>; and Ex. <NUM>-<NUM> at <NUM> for <NUM> minutes, followed by cooling in ambient air, as shown in <FIG>. As is evident from the figures, all of the glass-ceramic compositions of the example exhibited an XRD signature for manganese tungstate, MnWO<NUM> (i.e., Hübnerite).

Claim 1:
An article, comprising:
SiO<NUM> from <NUM> mol% to <NUM> mol%;
Al<NUM>O<NUM> from <NUM> mol% to <NUM> mol%;
B<NUM>O<NUM> from <NUM> mol% to <NUM> mol%;
WO<NUM> plus MoOs from <NUM> mol% to <NUM> mol%;
Fe<NUM>O<NUM> plus MnO<NUM> from <NUM> mol% to <NUM> mol%; and
R<NUM>O from <NUM> mol% to <NUM> mol%, wherein the R<NUM>O is one or more of Li<NUM>O, Na<NUM>O, K<NUM>O, Rb<NUM>O and Cs<NUM><NUM>,
wherein R<NUM>O - Al<NUM>O<NUM> ranges from -<NUM> mol% to +<NUM> mol%.