PHOSPHATE GLASSES WITH HIGH REFRACTIVE INDEX, LOW DENSITY AND REDUCED DISPERSION

Glass compositions include one or more of phosphorus oxide (P2O5), niobia (Nb2O5), titania (TiO2), potassium oxide (K2O) and lithium oxide (Li2O) as essential components and may optionally include barium oxide (BaO), zinc oxide (ZnO), V2O5 (vanadia), FeO (iron oxide) and other components.

FIELD

The present disclosure generally relates to phosphate glasses having a high refractive index and low density.

BACKGROUND

Glass is used in a variety of optical devices, examples of which include augmented reality devices, virtual reality devices, mixed reality devices, eye wear, etc. Desirable properties for this type of glass often include a high refractive index and a low density. Additional desirable properties may include high transmission in the visible and near-ultraviolet (near-UV) range of the electromagnetic spectrum and/or low optical dispersion. It can be challenging to find glasses having the desired combination of these properties and which can be formed from compositions having good glass-forming ability. For example, generally speaking, as the refractive index of a glass increases, the density also tends to increase. Species such as TiO2 and Nb2O5 are often added to increase the refractive index of a glass without increasing the density of the glass. However, these materials often absorb blue and UV light, which can undesirably decrease the transmittance of light in this region of the spectrum by the glass. Often, attempts to increase the refractive index of a glass while maintaining a low density, and without decreasing transmittance in the blue and UV region of the spectrum, can result in a decrease in the glass-forming ability of the material. For example, crystallization and/or liquid-liquid phase separation can occur during cooling of the glass melt at cooling rates that are generally acceptable in the industry. Typically, the decrease in glass-forming ability appears as the amount of certain species, such as ZrO2, Y2O3, Sc2O3, BaO, etc. increases.

Low density, high refractive index glasses often belong to one of two types of chemical systems, based on the glass formers used: (a) silicoborate or borosilicate glasses in which SiO2 and/or B2O3 are used as the main glass formers and (b) phosphate glasses in which P2O5 is used as a main glass former. Glasses which rely on other oxides as main glass formers, such as GeO2, TeO2, Bi2O3, and V2O5, can be challenging to use due to cost, glass-forming ability, optical properties, and/or production requirements.

Phosphate glasses can be characterized by a high refractive index and low density, however, phosphate glasses can be challenging to produce due to volatilization of P2O5 from the melts and/or risks of platinum incompatibility. In addition, phosphate glasses are often highly colored and may require an extra bleaching step to provide a glass having the desired transmittance characteristic. Furthermore, phosphate glasses exhibiting a high refractive index also tend to have an increase in optical dispersion, which may be usable for some applications.

In view of these considerations, there is a need for phosphate glasses having a high refractive index and low density, optionally in combination with a high transmittance in the visible and near UV-range, and/or which are made from compositions that provide good glass-forming ability.

SUMMARY

According to an embodiment of the present disclosure, a glass comprises a plurality of components, the glass having a composition of the components comprising greater than or equal to 25.5 mol. % P2O5, greater than or equal to 20.0 mol. % Nb2O5, greater than or equal to 0.5 mol. % and less than or equal to 40.0 mol. % TiO2, greater than or equal to 0.1 mol. % and less than or equal to 8.0 mol. % Li2O, a sum of Na2O+K2O greater than or equal to 1.0 mol. % and less than or equal to 30.0 mol. %, a sum of FeO+Fe2O3 greater than or equal to 0.000 mol. % and less than or equal to 0.020 mol. % and may optionally contain one or more components selected from Al2O3, B2O3, BaO, Bi2O3, CaO, CdO, Cs2O, GeO2, La2O3, MgO, MoO3, PbO, SiO2, SrO, Ta2O5, TeO2, WO3, ZrO2, Ga2O3 and ZnO, wherein the composition of the components is substantially free of V2O5, and wherein the composition of the components satisfies the conditions: P2O5/(TiO2+Nb2O5) [mol. %]≥0.30 and K2O−Na2O [mol. %]≥0.000, and the glass satisfies the conditions: Pn>1.9000 and Pd<3.80, where Pn is a refractive index parameter, calculated from the glass composition in terms of mol. % of the components according to the Formula (I):

Pd is a density parameter, calculated from the glass composition in terms of mol. % of the components according to the Formula (II):

where chemical formulas mean the content of corresponding components in the glass and an asterisk (*) means multiplication.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing specific details are set forth to provide a thorough understanding of various principles of the present disclosure. However, it will be apparent to one having ordinary skill in the art, having had the benefit of the present disclosure, that the present disclosure may be practiced in other embodiments that depart from the specific details disclosed herein. Moreover, descriptions of well-known devices, methods and materials may be omitted so as not to obscure the description of various principles of the present disclosure. Finally, wherever applicable, like reference numerals refer to like elements.

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 skilled 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. 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.

The term “component” refers to a material or compound included in a batch composition from which a glass is formed. Components include oxides, including but not limited to those expressed in Formulas (I)-(IV), and the claims. Representative components include B2O3, P2O5, Al2O3, CuO, Cu2O, RO, R2O, SnO2, MnO2, REmOn, SiO2, Ta2O5, ZnO, WO3, Nb2O5, TiO2, ZrO2, Bi2O3, TeO2, etc. Other representative components include halogens (e.g. F, Br, Cl). Whenever a component is included as a term in a mathematical expression or formula, it is understood that the component refers to the amount of the component in units of mol. % in the batch composition of the glass. For example, the expression “B2O3+P2O5” refers to the sum of the amount of B2O3 in units of mol. % and the amount of P2O5 in units of mol. % in the batch composition of the glass. A mathematical expression or formula is any expression or formula that includes a mathematical operator such as “+”, “−”, “*”, “/”, “min”, or “max”.

Unless otherwise specified, the amount or content of a component in a glass composition is expressed herein in units of mol. % (mole percent).

The term “formed from” can mean one or more of comprises, consists essentially of, or consists of. For example, a component that is formed from a particular material can comprise the particular material, consist essentially of the particular material, or consist of the particular material.

The terms “free” and “substantially free” are used interchangeably herein to refer to an amount and/or an absence of a particular component in a glass composition that is not intentionally added to the glass composition. It is understood that the glass composition may contain traces of a particular constituent component as a contaminant or a tramp in an amount of less than 0.10 mol. %.

As used herein, the term “tramp”, when used to describe a particular constituent component in a glass composition, refers to a constituent component that is not intentionally added to the glass composition and is present in an amount of less than 0.10 mol. %. Tramp components may be unintentionally added to the glass composition as an impurity in another constituent component and/or through migration of the tramp component into the composition during processing of the glass composition.

Unless otherwise specified, the term “glass” is used to refer to a glass made from a glass composition disclosed herein.

The symbol “*” means multiplication when used in any formula herein.

Temperature is expressed herein in units of ° C. (degrees Celsius).

Density is expressed herein in units of g/cm3.

The term “glass former” is used herein to refer to a component that, being solely present in the glass composition (i.e., without other components, except for tramps), is able to form a glass when cooling the melt at a rate of not greater than about 300° C./min.

The term “modifier”, as used herein, refers to the oxides of monovalent or divalent metals, i.e., R2O or RO, where “R” stands for a cation. Modifiers can be added to a glass composition to change the atomic structure of the melt and the resulting glass. In some embodiments, the modifier may change the coordination numbers of cations present in the glass formers (e.g., boron in B2O3), which may result in forming a more polymerized atomic network and, as a result, may provide better glass formation.

As used herein, the term “RO” refers to a total content of divalent metal oxides, the term “R2O” refers to a total content of monovalent metal oxides, and the term “Alk2O” refers to a total content of alkali metal oxides. The term R2O encompasses alkali metal oxides (Alk2O), in addition to other monovalent metal oxides, such as Ag2O, Tl2O, and Hg2O, for example.

The measured density values for the glasses reported herein were measured at room temperature in units of g/cm3 by Archimedes method in water with an error of 0.001 g/cm3. As used herein, density measurements at room temperature (specified as dRT) are indicated as being measured at 20° C.

As used herein, good glass forming ability refers to a resistance of the melt to devitrification as the material cools. Glass forming ability can be measured by determining the critical cooling rate of the melt. The terms “critical cooling rate” or “vcr” are used herein to refer to the minimum cooling rate at which a melt of a given composition forms a glass free of crystals visible under an optical microscope under magnification of 500×. The critical cooling rate can be used to measure the glass-forming ability of a composition, i.e., the ability of the melt of a given glass composition to form glass when cooling. Generally speaking, the lower the critical cooling rate, the better the glass-forming ability.

The term “liquidus temperature” (Tliq) is used herein to refer to a temperature above which the glass composition is completely liquid with no crystallization of constituent components of the glass. The liquidus temperature values reported herein were obtained by measuring samples using either DSC or by isothermal hold of samples wrapped in platinum foil. For samples measured using DSC, powdered samples were heated at 10 K/min to 1250° C. The end of the endothermal event corresponding to the melting of crystals was taken as the liquidus temperature. For the second technique (isotactic hold), a glass block (about 1 cm3) was wrapped in platinum foil, to avoid volatilization, and placed in a furnace at a given temperature for 17 hours. The glass block was then observed under an optical microscope to check for crystals.

The refractive index values reported herein were measured at room temperature, unless otherwise specified. The refractive index values for a glass sample were measured using a Metricon Model 2010 prism coupler refractometer with an error of about ±0.0002. Using the Metricon, the refractive index of a glass sample was measured at two or more wavelengths of about 406 nm, 473 nm, 532 nm, 633 nm, 828 nm, and 1064 nm. The measured dependence characterizes the dispersion and was then fitted with a Cauchy's law equation or Sellmeier equation to allow for calculation of the refractive index of the sample at a given wavelength of interest between the measured wavelengths. The term “refractive index nd” is used herein to refer to a refractive index calculated as described above at a wavelength of 587.56 nm, which corresponds to the helium d-line wavelength. The term “refractive index nC” is used herein to refer to a refractive index calculated as described above at a wavelength of 656.3 nm. The term “refractive index nr” is used herein to refer to a refractive index calculated as described above at a wavelength of 486.1 nm. The term “refractive index ng” is used herein to refer to a refractive index calculated as described above at a wavelength of 435.8 nm.

As used herein, the terms “high refractive index” or “high index” refer to a refractive index value of a glass that is greater than or equal to 1.8000, unless otherwise indicated. In embodiments the terms “high refractive index” or “high index” refer to a refractive index value of a glass that is greater than or equal to 1.8500, greater than or equal to 1.9000, or greater than or equal to 1.9500, or greater than or equal to 2.0000.

The terms “dispersion” and “optical dispersion” are used interchangeably to refer to a difference or ratio of the refractive indices of a glass sample at predetermined wavelengths. One numerical measure of optical dispersion reported herein is the Abbe number, which can be calculated by the formula: νx=(nx−1)/(nF−nC), where “x” in the present disclosure stands for one of the commonly used wavelengths (for example, 587.56 nm [d-line] for νd or 589.3 nm [D-line] for νD, nx is the refractive index at this wavelength (for example, nd for νd and nD for νD), and nF and nC are refractive indices at the wavelengths 486.1 nm (F-line) and 656.3 nm (C-line), respectively. The numerical values of νd and νD differ very slightly, mostly within ±0.1% to ±0.2%. As reported herein, the dispersion of a glass sample is represented by the Abbe number (νd), which characterizes the relationship between the refractive indices of the sample at three different wavelengths according to the following formula: νd=(nd−1)/(nF−nC), where nd is the calculated refractive index at 587.56 nm (d-line), nF is the calculated refractive index at 486.1 nm, and nC is the calculated refractive index at 656.3 nm. A higher Abbe number corresponds to a lower optical dispersion.

The glass transition temperature (Tg) is measured by differential scanning calorimeter (DSC) at the heating rate of 10 K/min after cooling in air.

Glass composition may include zinc oxide (ZnO). Zinc oxide provides a comparably good refractive index to density ratio and may sometimes increase the solubility of titania, which indirectly increases the refractive index of glasses. However, it was found that in some embodiments, at high concentrations of ZnO, the glass forming ability of the melt decreases and the melt may tend to crystallize during cooling. That is why the amount of ZnO in the glasses of the present disclosure is limited, or glass compositions may be free of ZnO. In embodiments, the glass composition may contain zinc oxide (ZnO) in an amount from greater than or equal to 0.0 mol. % to less than or equal to 5.0 mol. % and all ranges and sub-ranges between the foregoing values. In some other embodiments, the glass composition may contain ZnO in an amount less than or equal to 5.0 mol. %, or less than or equal to 2.5 mol. %, or less than or equal to 2.0 mol. %, or less than or equal to 1.8 mol. %, or less than or equal to 1.6 mol. %, or less than or equal to 0.1 mol. %. In some more embodiments, the glass composition may contain ZnO in an amount greater than or equal to 0.0 mol. % and less than or equal to 2.0 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 1.8 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 1.6 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 0.1 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 5.0 mol. %.

Glass composition may include barium oxide (BaO). Barium oxide may increase the solubility of high index components, such as TiO2 and Nb2O5, more than other divalent metal oxides, which may indirectly lead to a further increase in the refractive index at comparably low density. However, barium is a heavy element and, being added in a high amount, may increase the density of glass. Also, at high concentration, it may cause crystallization of such minerals as barium titanate (BaTiO3), barium niobate (BaNb2O6), barium orthophosphate (Ba3P2O8) and others, which may cause crystallization of a melt when cooling. Accordingly, the amount of BaO in glasses of the present disclosure is limited. In embodiments, the glass composition may contain barium oxide (BaO) in an amount from greater than or equal to 0.0 mol. % to less than or equal to 10.0 mol. % and all ranges and sub-ranges between the foregoing values. In some embodiments, the glass composition may contain BaO in an amount greater than or equal to 0.0 mol. %, or greater than or equal to 1.5 mol. %, or greater than or equal to 5.0 mol. %, or greater than or equal to 6.0 mol. %. In some other embodiments, the glass composition may contain BaO in an amount less than or equal to 10.0 mol. %, or less than or equal to 8.5 mol. %, or less than or equal to 8.0 mol. %, or less than or equal to 7.75 mol. %, or less than or equal to 5.0 mol. %. In some more embodiments, the glass composition may contain BaO in an amount greater than or equal to 0.0 mol. % and less than or equal to 11.0 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 10.0 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 8.5 mol. %, or greater than or equal to 1.5 mol. % and less than or equal to 7.75 mol. %, or greater than or equal to 5.99 mol. % and less than or equal to 8.49 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 5.0 mol. %, or greater than or equal to 1.5 mol. % and less than or equal to 10.0 mol. %, or greater than or equal to 1.5 mol. % and less than or equal to 5.0 mol. %, or greater than or equal to 5.0 mol. % and less than or equal to 10.0 mol. %, or greater than or equal to 5.0 mol. % and less than or equal to 7.75 mol. %.

The glass may include calcium oxide (CaO) and/or strontium oxide (SrO) independently or in combination, or in combination with BaO. The glass composition may include a sum of CaO+SrO+BaO greater than or equal to 0.0 mol. % to less than or equal to 15.0 mol. % and all ranges and sub-ranges between the foregoing values. In embodiments, the glass composition may contain a sum of CaO+SrO+BaO greater than or equal to 0.0 mol. %, or greater than or equal to 1.5 mol. %, or greater than or equal to 3.0 mol. %, or greater than or equal to 4.5 mol. %, or greater than or equal to 6.0 mol. %, or greater than or equal to 7.5 mol. %. In some other embodiments, the glass composition may contain a sum of CaO+SrO+BaO less than or equal to 15.0 mol. %, or less than or equal to 12.0 mol. %, or less than or equal to 10.5 mol. %, or less than or equal to 9.0 mol. %, or less than or equal to 7.5 mol. %. In some more embodiments, the glass composition may contain a sum of CaO+SrO+BaO greater than or equal to 0.0 mol. % and less than or equal to 15.0 mol. %, or greater than or equal to 1.5 mol. % and less than or equal to 12.0 mol. %, or greater than or equal to 3.0 mol. % and less than or equal to 10.5 mol. %, or greater than or equal to 4.5 mol. % and less than or equal to 9.0 mol. %, or greater than or equal to 6.0 mol. % and less than or equal to 9.0 mol. %.

Glass composition may include vanadia (V2O5). Vanadia provides the highest ratio of the refractive index to density among all oxides. However, vanadia may cause undesirable dark or even black coloring and may also raise environmental concerns. For these reasons, the content of vanadia in the glasses of the present disclosure is limited, or glass compositions may be free of V2O5. In embodiments, the glass composition may contain vanadia (V2O5) in an amount from greater than or equal to 0.0 mol. % to less than or equal to 0.05 mol. % and all ranges and sub-ranges between the foregoing values. In some other embodiments, the glass composition may contain V2O5 in an amount less than or equal to 0.05 mol. % or less than or equal to 0.025 mol. %. In some more embodiments, the glass composition may contain V2O5 in an amount greater than or equal to 0.0 mol. % and less than or equal to 0.05 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 0.025 mol. %.

In some embodiments, glass composition may have limitations for a sum FeO+Fe2O3. Iron oxides (FeO and Fe2O3), and especially FeO, may provide undesirable coloration to the glasses of the present disclosure, even when added in very low concentrations, such as 0.02 mol. %, 0.01 mol. %, or even 0.007 mol. %. Accordingly, the glasses of the present disclosure are substantially free of iron oxides. However, iron oxides may be presented in the glasses of the present disclosure in very small concentrations as impurities in the starting materials. In some other embodiments, the glass composition may contain a sum of FeO+Fe2O3 in an amount less than or equal to 0.02 mol. % or less than or equal to 0.01 mol. %. In some more embodiments, the glass composition may contain FeO+Fe2O3 in an amount greater than or equal to 0.0 mol. % and less than or equal to 0.02 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 0.01 mol. %.

In some embodiments, glass composition may have limitations for a sum Na2O+K2O. Adding the alkali metal oxides other than Li2O, i.e., Na2O and K2O, is necessary to protect the glasses of the present disclosure from devitrification when cooling. This is caused by the devitrification tendency of lithium-rich glasses. Preferably, to provide better protection from devitrification, the glasses of the present disclosure contain, at least, two different alkali oxides, one of which is Li2O and another may be Na2O, K2O or their combination. Accordingly, the glasses of the present disclosure include, at least, one of Na2O and K2O, or their combination. However, when the sum of Na2O+K2O is high, the glasses of the present disclosure may have a lower viscosity and, therefore, lower liquidus viscosity, which adversely decrease the durability of glasses to devitrification when cooling. Accordingly, the content of Na2O+K2O is preferably limited. In some embodiments, the glass composition may have a sum of Na2O+K2O greater than or equal to 1.0 mol. %, or greater than or equal to 6.0 mol. %, or greater than or equal to 10.0 mol. %, or greater than or equal to 20.0 mol. %. In some other embodiments, the glass composition may have a sum of Na2O+K2O less than or equal to 30.0 mol. %, or less than or equal to 20.0 mol. %, or less than or equal to 11.0 mol. %, or less than or equal to 10.0 mol. %. In some more embodiments, the glass composition may have a sum of Na2O+K2O greater than or equal to 1.0 mol. % and less than or equal to 30.0 mol. %, or greater than or equal to 1.0 mol. % and less than or equal to 20.0 mol. %, or greater than or equal to 1.0 mol. % and less than or equal to 11.0 mol. %, or greater than or equal to 1.0 mol. % and less than or equal to 10.0 mol. %, or greater than or equal to 6.0 mol. % and less than or equal to 30.0 mol. %, or greater than or equal to 6.0 mol. % and less than or equal to 20.0 mol. %, or greater than or equal to 6.0 mol. % and less than or equal to 11.0 mol. %, or greater than or equal to 6.0 mol. % and less than or equal to 10.0 mol. %, or greater than or equal to 10.0 mol. % and less than or equal to 30.0 mol. %, or greater than or equal to 10.0 mol. % and less than or equal to 20.0 mol. %, or greater than or equal to 10.0 mol. % and less than or equal to 11.0 mol. %.

In some embodiments to protect the glass from devitrification, it may be desirable for the glass composition to include more K2O than Na2O. In embodiments, the glass composition may have a difference K2O−Na2O greater than or equal to 0.00 mol. %, or greater than or equal to 0.25 mol. %, or greater than or equal to 0.50 mol. %, or greater than or equal to 1.0 mol. %, or greater than or equal to 1.50 mol. %, or greater than or equal 2.0 mol. %, or greater than or equal to 3.0 mol. %, or greater than or equal to 4.0 mol. %, or greater than or equal 5.0 mol. %, or greater than or equal to 7.0 mol. %, or greater than or equal to 9.0 mol. %. In some other embodiments, the glass composition may have a difference K2O−Na2O less than or equal to 15.0 mol. %, or less than or equal to 12.0 mol. %, or less than or equal to 10.0 mol. %, or less than or equal to 8.0 mol. %. In some more embodiments, the glass composition may have a difference K2O−Na2O greater than or equal to 0.0 mol. % and less than or equal to 15.0 mol. %, or greater than or equal to 0.50 mol. % and less than or equal to 12.0 mol. %, or greater than or equal to 1.0 mol. % and less than or equal to 10.0 mol. %, or greater than or equal to 2.0 mol. % and less than or equal to 8.0 mol. %.

In some embodiments to protect the glass from devitrification, it may be desirable for the glass composition to include more Li2O than Na2O. In embodiments, the glass composition may have a difference Li2O−Na2O greater than or equal to 0.00 mol. %, or greater than or equal to 0.25 mol. %, or greater than or equal to 0.50 mol. %, or greater than or equal to 0.75 mol. %, or greater than or equal to 1.00 mol. %, or greater than or equal 1.25 mol. %, or greater than or equal to 1.50 mol. %, or greater than or equal to 1.75 mol. %, or greater than or equal 2.00 mol. %. In some other embodiments, the glass composition may have a difference Li2O−Na2O less than or equal to 5.0 mol. %, or less than or equal to 4.0 mol. %, or less than or equal to 3.0 mol. %, or less than or equal to 2.0 mol. %. In some more embodiments, the glass composition may have a difference Li2O−Na2O greater than or equal to 0.0 mol. % and less than or equal to 5.0 mol. %, or greater than or equal to 0.25 mol. % and less than or equal to 4.0 mol. %, or greater than or equal to 0.50 mol. % and less than or equal to 3.0 mol. %.

In some embodiments, to control devitrification, it may be desirable for the glass compositionto have limitations for a sum of Li2O+Na2O+K2O. In embodiments, the glass composition may have a sum of Li2O+Na2O+K2O greater than or equal to 0.0 mol. %, or greater than or equal to 1.0 mol. %, or greater than or equal to 2.0 mol. %, or greater than or equal to 4.0 mol. %, or greater than or equal to 6.0 mol. %, or greater than or equal 8.0 mol. %, or greater than or equal to 10.0 mol. %, or greater than or equal to 12.0 mol. %, or greater than or equal 14.0 mol. %, or greater than or equal to 15.0 mol. %. In some other embodiments, the glass composition may have a sum of Li2O+Na2O+K2O less than or equal to 25.0 mol. %, or less than or equal to 22.0 mol. %, or less than or equal to 20.0 mol. %, or less than or equal to 17.0 mol. %. In some more embodiments, the glass composition may have a sum of Li2O+Na2O+K2O greater than or equal to 0.0 mol. % and less than or equal to 25.0 mol. %, or greater than or equal to 5.0 mol. % and less than or equal to 25.0 mol. %, or greater than or equal to 10.0 mol. % and less than or equal to 25.0 mol. %, or greater than or equal to 15.0 mol. % and less than or equal to 25.0 mol. %, or greater than or equal to 1.00 mol. % and less than or equal to 22.0 mol. %, or greater than or equal to 2.0 mol. % and less than or equal to 20.0 mol. %, or greater than or equal to 4.0 mol. % and less than or equal to 17.0 mol. %.

In some embodiments, to control devitrification, the glass composition may have limitations for the amount of Na2O. In embodiments, the glass composition may have an amount of Na2O greater than or equal to 0.00 mol. %, or greater than or equal to 0.25 mol. %, or greater than or equal to 0.50 mol. %. In some other embodiments, the glass composition may have an amount of Na2O less than or equal to 5.0 mol. %, or less than or equal to 4.0 mol. %, or less than or equal to 3.0 mol. %, or less than or equal to 2.0 mol. %, or less than or equal to 1.5 mol. %, or less than or equal to 1.0 mol. %, or less than or equal to 0.50 mol. %, or less than or equal to 0.25 mol. %. In embodiments, the glass composition is substantially free of Na2O. In some more embodiments, the glass composition may have an amount of Na2O greater than or equal to 0.0 mol. % and less than or equal to 5.0 mol. %, greater than or equal to 0.0 mol. % and less than or equal to 2.0 mol. %, or greater than or equal to 0.0 mol. % and less than or equal to 0.5 mol. %, or greater than or equal to 0.10 mol. % and less than or equal to 3.0 mol. %, or greater than or equal to 0.20 mol. % and less than or equal to 2.0 mol. %.

In some embodiments, glass composition may have limitations for a ratio P2O5/(TiO2+Nb2O5). The ratio P2O5/(TiO2+Nb2O5) characterizes the balance between the glass-forming ability (or durability against devitrification) provided by P2O5 and high refractive index provided by TiO2 and Nb2O5. The higher the ratio P2O5/(TiO2+Nb2O5), the better the glass-forming ability is, but the more difficult it is to reach high refractive index. Accordingly, for the glasses of the present disclosure with high refractive index, it is challenging to maintain the high ratio P2O5/(TiO2+Nb2O5). However, a minimum value of this ratio, at least, greater than or equal to 0.30, may be needed to inhibit devitrification and/or promote glass forming. In the present disclosure, unless otherwise specified, the quantity P2O5/(TiO2+Nb2O5) is expressed in terms of a ratio of mol. %. In some embodiments, the glass may have a ratio P2O5/(TiO2+Nb2O5) greater than or equal to 0.30, or greater than or equal to 0.40, or greater than or equal to 0.45, or greater than or equal to 0.46, or greater than or equal to 0.47, or greater than or equal to 0.49, or greater than or equal to 0.50, or greater than or equal to 0.51, or greater than or equal to 0.52, or greater than or equal to 0.53, or greater than or equal to 0.54. In some other embodiments, the glass may have a ratio P2O5/(TiO2+Nb2O5) less than or equal to 0.58, or less than or equal to 0.55, or less than or equal to 0.53, or less than or equal to 0.51, or less than or equal to 0.50, or less than or equal to 0.40. In some more embodiments, the glass may have a ratio P2O5/(TiO2+Nb2O5) greater than or equal to 0.42 and less than or equal to 0.62, or greater than or equal to 0.44 and less than or equal to 0.60, or greater than or equal to 0.46 and less than or equal to 0.58, or greater than or equal to 0.30 and less than or equal to 0.51, or greater than or equal to 0.30 and less than or equal to 0.50, or greater than or equal to 0.30 and less than or equal to 0.40, or greater than or equal to 0.40 and less than or equal to 0.51, or greater than or equal to 0.40 and less than or equal to 0.50, or greater than or equal to 0.45 and less than or equal to 0.51, or greater than or equal to 0.45 and less than or equal to 0.50, or greater than or equal to 0.46 and less than or equal to 0.51, or greater than or equal to 0.46 and less than or equal to 0.50, or greater than or equal to 0.47 and less than or equal to 0.51.

In some embodiments, the glass may have a refractive index at 587.56 nm nd from greater than or equal to 1.8500 to less than or equal to 1.9770 and all ranges and sub-ranges between the foregoing values. In some embodiments, the glass may have the refractive index at 587.56 nm nd greater than or equal to 1.8500, or greater than or equal to 1.8750, or greater than or equal to 1.9000, or greater than or equal to 1.9300, or greater than or equal to 1.9400, or greater than or equal to 1.9470, or greater than or equal to 1.9500, or greater than or equal to 1.9550, or greater than or equal to 1.9570, or greater than or equal to 1.9670. In some other embodiments, the glass may have the refractive index at 587.56 nm nd less than or equal to 1.9770, or less than or equal to 1.9700, or less than or equal to 1.9670, or less than or equal to 1.9660, or less than or equal to 1.9570, or less than or equal to 1.9500, or less than or equal to 1.9470. In some more embodiments, the glass may have the refractive index at 587.56 nm nd greater than or equal to 1.9000 and less than or equal to 1.9770, or greater than or equal to 1.9000 and less than or equal to 1.9470, or greater than or equal to 1.9300 and less than or equal to 1.9470.

In some embodiments, the glass may have a refractive index parameter Pn from greater than or equal to 1.8500 to less than or equal to 1.9770 and all ranges and sub-ranges between the foregoing values. In some embodiments, the glass may have the refractive parameter Pn greater than or equal to 1.8500, or greater than or equal to 1.8750, or greater than or equal to 1.9000, or greater than or equal to 1.9300, or greater than or equal to 1.9400, or greater than or equal to 1.9470, or greater than or equal to 1.9500, or greater than or equal to 1.9550, or greater than or equal to 1.9570, or greater than or equal to 1.9670. In some other embodiments, the glass may have the parameter Pn less than or equal to 1.9770, or less than or equal to 1.9700, or less than or equal to 1.9670, or less than or equal to 1.9660,or less than or equal to 1.9570, or less than or equal to 1.9500, or less than or equal to 1.9470. In some more embodiments, the glass may have the refractive index parameter Pn greater than or equal to 1.9000 and less than or equal to 1.9770, or greater than or equal to 1.9000 and less than or equal to 1.9470, or greater than or equal to 1.9300 and less than or equal to 1.9470

In some embodiments, the glass may have a density at room temperature dRT from greater than or equal to 0.0 g/cm3 to less than or equal to 3.81 g/cm3 and all ranges and sub-ranges between the foregoing values. In some embodiments, the glass may have the density at room temperature dRT greater than or equal to 1.00 g/cm3, or greater than or equal to 2.00 g/cm3, or greater than or equal to 3.40 g/cm3, or greater than or equal to 3.59 g/cm3. In some other embodiments, the glass may have the density at room temperature dRT less than or equal to 3.81 g/cm3, or less than or equal to 3.70 g/cm3, or less than or equal to 3.60 g/cm3, or less than or equal to 3.50 g/cm3, or less than or equal to 3.40 g/cm3. In some more embodiments, the glass may have the density at room temperature dRT greater than or equal to 2.00 g/cm3 and less than or equal to 3.80 g/cm3, or greater than or equal to 2.10 g/cm3 and less than or equal to 3.80 g/cm3, or greater than or equal to 2.25 g/cm3 and less than or equal to 3.80 g/cm3, or greater than or equal to 2.50 g/cm3 and less than or equal to 3.70 g/cm3, or greater than or equal to 2.75 g/cm3 and less than or equal to 3.60 g/cm3.

In some embodiments, the glass may have a density parameter Pd greater than or equal to 2.00 g/cm3, or greater than or equal to 3.40 g/cm3, or greater than or equal to 3.59 g/cm3. In some other embodiments, the glass may have the density parameter Pd less than or equal to 3.81 g/cm3, or less than or equal to 3.70 g/cm3, or less than or equal to 3.60 g/cm3, or less than or equal to 3.50 g/cm3, or less than or equal to 3.40 g/cm3. In some more embodiments, the glass may have the density parameter Pd greater than or equal to 2.00 g/cm3 and less than or equal to 3.80 g/cm3, or greater than or equal to 2.10 g/cm3 and less than or equal to 3.80 g/cm3, or greater than or equal to 2.25 g/cm3 and less than or equal to 3.80 g/cm3, or greater than or equal to 2.50 g/cm3 and less than or equal to 3.70 g/cm3, or greater than or equal to 2.75 g/cm3 and less than or equal to 3.60 g/cm3.

In some embodiments, the glass may have a refractive index to density ratio (“refraction”) (nd−1)/dRT [cm3/g] greater than or equal to 0.24. In some embodiments, the glass may have the refractive index to density ratio (nd−1)/dRT [cm3/g] greater than or equal to 0.25, or greater than or equal to 0.26, or in the range from 0.24 to 0.27.

In some embodiments, the glass may have a refraction parameter Pref [cm3/g] greater than or equal to 0.24. In some embodiments, the glass may have the refractive parameter Pref [cm3/g] greater than or equal to 0.25, or greater than or equal to 0.26, or in the range from 0.24 to 0.27.

In some embodiments, the glass may have an Abbe number νd less than or equal to 19.00. In some other embodiments, the glass may have the Abbe number νd less than or equal to 18.75, or less than or equal to 18.50, or less than or equal to 18.25, or less than or equal to 18.00, or less than or equal to 17.75, or greater than or equal to 16.00, or greater than or equal to 16.50, or greater than or equal to 17.00, or greater than or equal to 17.25.

In some embodiments, the glass may have a dispersion parameter Pν less than or equal to 19.00. In some other embodiments, the glass may have a dispersion parameter Pν less than or equal to 18.75, or less than or equal to 18.50, or less than or equal to 18.25, or less than or equal to 18.00, or less than or equal to 17.75, or greater than or equal to 16.00, or greater than or equal to 16.50, or greater than or equal to 17.00, or greater than or equal to 17.25.

In some embodiments, the glass may have a liquidus temperature Tliq less than or equal to 1200° C. In some other embodiments, the glass may have the liquidus temperature Tliq less than or equal to 1175° C., or less than or equal to 1150° C., or less than or equal to 1125° C., or less than or equal to 1100° C., or less than or equal to 1075° C.

In some embodiments, the glass may have a glass transition temperature Tg greater than or equal to 600° C. In some embodiments, the glass may have the glass transition temperature Tg greater than or equal to 620° C., or greater than or equal to 640° C., or greater than or equal to 650° C.

In some embodiments, the glass may have the density at room temperature dRT less than or equal to 4.50. In some other embodiments, the glass may have the dRT less than or equal to 4.50 or less than or equal to 4.50, or less than or equal to 3.80.

Refractive index nd, density dRT, Abbe number νd and refraction (nd−1)/dRT are properties of a glass that can be predicted from the glass composition. A linear regression analysis of the Exemplary Glasses of the present disclosure in the EXAMPLES section below and other glass compositions reported in the literature was performed to determine equations that can predict the composition dependences of the refractive index nd, density dRT, Abbe number νd, and refraction (nd−1)/dRT.

The training dataset of glass compositions satisfying the criteria specified in Table 1 below and having measured values of the properties of interest, about 100 glass compositions for each property (nd, density dRT, νd and refraction), was randomly selected from the literature data presented in the publicly available SciGlass Information System database and from the Exemplary Glasses from the embodiments presented herein. The linear regression analysis on the above-specified dataset was used to determine the formulas (I)-(IV) presented in Table 2 below for predictive parameters Pn, Pd, Pν, and Pref, respectively. Another subset of glass compositions satisfying the criteria of Table 1 was used as a validation set to evaluate the ability to interpolate within the compositional limits of Table 1 and was used to establish the standard deviations specified in the Table 2. An external dataset of prior art glass compositions, also randomly selected from the SciGlass Information System database, was used to evaluate the ability to predict the properties (nd, dRT, νd, and refraction) outside of the compositional limits of Table 1 with reasonable accuracy. Multiple iterations of this process were performed in order to determine the best formula for each property (nd, dRT, νd, and refraction). Formulas (I)-(IV) in Table 2 are the result of the analysis.

The data for the Comparative Glass compositions used in the linear regression modeling, including the training dataset, validation dataset and external dataset were obtained from the publically available SciGlass Information System database. Formulas (I), (II), (III) and (IV) below were obtained from the linear regression analysis and used to predict the refractive index nd, density, Abbe number and refraction, respectively, of the glasses:

In Formulas (I), (II), (III) and (IV) and Tables 1 and 2, refractive index parameter Pn is a parameter that predicts the refractive index at 587.56 nm, calculated from the components of the glass composition expressed in mol. %; density parameter Pd is a parameter that predicts the density at room temperature dRT [g/cm3], calculated from the components of the glass composition expressed in mol. %; dispersion parameter Pν is a parameter that predicts the Abbe number νd, calculated from the components of the glass composition expressed in mol. %; and refraction parameter Pref is a parameter that predicts the refractive index to density ratio (nd−1)/dRT (“refraction”) [cm3/g], calculated from the components of the glass composition expressed in mol. %. For dispersion parameter Pν, logarithmic scale was applied when performing the regression analysis.

In Formulas (I), (II), (III) and (IV), each component of the glass composition is listed in terms of its chemical formula, where the chemical formula refers to the concentration of the component expressed in mol. %. For example, for purposes of Formulas (I), (II), (III) and (IV), Al2O3 refers to the concentration of Al2O3, expressed in mol. %, in the glass composition. It is understood that not all components listed in Formulas (I), (II), (III) and (IV) are necessarily present in a particular glass composition and that Formulas (I), (II), (III) and (IV) are equally valid for glass compositions that contain less than all of the components listed in the formulas. It is further understood that Formulas (I), (II), (III) and (IV) are also valid for glass compositions within the scope and claims of the present disclosure that contain components in addition to the components listed in the formulas. If a component listed in Formulas (I), (II), (III) and (IV) is absent in a particular glass composition, the concentration of the component in the glass composition is 0 mol. % and the contribution of the component to the value calculated from the formulas is zero. In Table 1, RmOn is a total sum of all oxides, R2O is a total sum of monovalent metal oxides and RO is a total sum of divalent metal oxides.

Composition Space Used for Modeling

Property

Component limits

RmOn
99
Not
99
Not
99
Not
99
Not

limited

limited

limited

limited

limited

limited

limited

limited

limited
limited
limited
limited
limited

limited

R2O + RO − P2O5
−10
Not
Not
Not
Not
Not
Not
Not

limited
limited
limited
limited
limited
limited
limited

R2O + RO − TiO2
−5
Not
Not
Not
Not
Not
Not
Not

limited
limited
limited
limited
limited
limited
limited

V2O5
Not
Not
0
80
Not
Not
Not
Not

limited
limited

limited
limited
limited
limited

TiO2 + Nb2O5 + WO3 +
Not
Not
25
Not
Not
Not
Not
Not

limited
limited
limited
limited
limited

Other species
0
Not
0
Not
0
Not
0
Not

limited

limited

limited

limited

Property prediction models

Predicting
Regression
Composition
Standard

Property
Abbreviation
Unit
Parameter
Formula
Unit
Deviation

Refractive index at
nd

temperature

density ratio

FIG. 1 is a plot of the parameter Pn calculated by Formula (I) as a function of measured refractive index nd for some Comparative Glasses (“Comp. Glasses”) taken from the literature and some Exemplary Glasses (“Ex. Glasses”). As illustrated by the data in FIG. 1, the compositional dependence of the parameter Pn had a standard deviation within a range of ±0.021 unit of the measured na for the majority of glasses.

FIG. 2 is a plot of the parameter Pd calculated by Formula (II) as a function of measured density dRT for some Comparative Glasses (“Comp. Glasses”) taken from the literature and some Exemplary Glasses (“Ex. Glasses”). As illustrated by the data in FIG. 2, the compositional dependence of the parameter Pd had a standard deviation within a range of ±0.20 unit of the measured dRT for the majority of glasses.

FIG. 3 is a plot of the parameter Pν calculated by Formula (III) as a function of measured Abbe number νd for some Comparative Glasses (“Comp. Glasses”) taken from the literature and some Exemplary Glasses (“Ex. Glasses”). As illustrated by the data in FIG. 3, the compositional dependence of the parameter Pν had a standard deviation within a range of ±0.66 unit of the measured νd for the majority of glasses.

FIG. 4 is a plot of the parameter Pref calculated by Formula (IV) as a function of measured refraction (nd−1)/dRT for some Comparative Glasses (“Comp. Glasses”) taken from the literature and some Exemplary Glasses (“Ex. Glasses”). As illustrated by the data in FIG. 4, the compositional dependence of the parameter Pref had a standard deviation within a range of ±0.0049 unit of the measured (nd−1)/dRT for the majority of glasses.

Table 3 identifies the combination of components and their respective amounts according to some embodiments of the present disclosure. The Exemplary Glasses A in Table 3 may include additional components according to any aspects of the present disclosure as described herein.

Exemplary Glasses A

Exemplary Glasses A according to embodiments of the present disclosure may satisfy the following condition:

where the chemical formulas refer to the amounts of the components in the glass, expressed in mol. %.

According to some embodiments of the present disclosure, Exemplary Glasses A may also satisfy the following condition:

where the chemical formulas refer to the amounts of the components in the glass, expressed in mol. %.

According to some embodiments of the present disclosure, Exemplary Glasses A may also have a refractive index at 587.56 nm nd or refractive index parameter Pn of greater than or equal to 1.9000.

According to some embodiments of the present disclosure, Exemplary Glasses A may also have a density at room temperature dRT [g/cm3] or density parameter Pd of less than or equal to 3.80.

According to some embodiments of the present disclosure, Exemplary Glasses A may also have an Abbe number νd or dispersion parameter Pν of less than or equal to 18.00.

According to some embodiments of the present disclosure, Exemplary Glasses A may also have a refraction (nd−1)/dRT [cm3/g] or refraction parameter Pref of greater than or equal to 0.24.

EXAMPLES

The following examples 1-49 in Table 4 describe various features and advantages provided by the disclosure, and are in no way intended to limit the invention and appended claims. All compositions in Table 4 are listed in mol. % and the values listed for Pn, Pd, Pν, and Pref were computed from Formulas (I)-(IV), respectively.

The exemplary glasses of Table 4 were prepared using high-purity oxide and phosphate raw materials in the form of fine powders. Nb2O5 was batched as niobium oxide, which in some cases included a non-negligible amount of tantalum oxide, Ta2O5. TiO2 was batched as a mixture of titanium dioxide and titanium pyrophosphate, the latter being used to obtain the high P2O5 contents of some of the inventive glasses. Li2O and K2O were batched as monobasic orthophosphates, LiH2PO4 and KH2PO4.BaO was batched as either barium metaphosphate, BaPO3, or as barium dihydrogen phosphate, Ba(H2PO4)2.CaO was batched as calcium dihydrogen phosphate monohydrate, Ca(H2PO4)2.H2O. ZnO was batched as zinc pyrophosphate, ZnP2O7. Batches were prepared by weighing oxides into clean plastic bottles, adding alumina media to aid in breaking up soft agglomerates, and mixing using a Turbula® shaker mixer for one hour. The mixtures were transferred from the bottle to a crucible prior to melting. For most of the examples, the crucible material was fused quartz, and as a result a small amount of SiO2 (≤1 mol %) is incorporated into those glasses. When fused quartz is used as a crucible material, the glasses described herein are free of platinum (Pt). In some of the examples, the crucible material was platinum. However, despite its reputation for being chemically inert, a very small amount of platinum is incorporated into the inventive glasses when it is used as a crucible material, resulting in appreciable absorption at visible wavelengths. Some contact with platinum may be required to enable manufacturing: however, the amount of platinum that is incorporated into the glass as a result of such contact is expected to be less than 5.0 ppm, more preferably <1.0 ppm, to achieve the high transmittance at visible wavelengths. In preferred embodiments, the concentration of Pt in glasses in accordance with the present disclosure is less than or equal to 5.0 ppm, or less than or equal to 4.0 ppm, or less than or equal to 3.5 ppm, or less than or equal to 3.0 ppm, or less than or equal to 2.5 ppm, or less than or equal to 2.0 ppm, or less than or equal to 1.5 ppm, or less than or equal to 1.0 ppm.

The crucibles were placed into refractory outer crucibles, covered with refractory lids, and loaded into a furnace heated by silicon carbide glow bars. The furnace temperature was 1300° C., though it fell below this briefly after loading samples. A typical melt schedule is as follow. Nine crucibles containing 1 kg of batch each were loaded simultaneously into the furnace at 1300° C. After 45 min, the crucibles were removed from the furnace one at a time, the lids were removed, and the glass was poured onto a steel plate. The resulting patty of still-incandescent glass was plunged into a bucket of cold water to shatter it into fine cullet. The cullet was dried, loaded into a crucible of the same type used for the first melt, covered, and melted again at 1300° C. for 45 minutes. After this time, the crucible was removed from the furnace, the lid was removed, and the glass was poured into a mold. Best results were obtained when the mold was pre-heated to at least 300° C. In some cases, the molten glass was stirred with a rod of fused quartz to maximize homogeneity of the final glass. All glasses were annealed at 650° C. for 2 h, then cooled at approximately 1° C./min to room temperature.

Exemplary Glass Compositions

The following non-limiting aspects are encompassed by the present disclosure. To the extent not already described, any one of the features of the first through the sixty-ninth aspect may be combined in part or in whole with features of any one or more of the other aspects of the present disclosure to form additional aspects, even if such a combination is not explicitly described.

According to a first aspect, the glass comprises a plurality of components, the glass having a composition of the components comprising greater than or equal to 25.5 mol. % P2O5, greater than or equal to 20.0 mol. % Nb2O5, greater than or equal to 0.5 mol. % and less than or equal to 40.0 mol. % TiO2, greater than or equal to 0.1 mol. % and less than or equal to 8.0 mol. % Li2O, a sum of Na2O+K2O is greater than or equal to 1.0 mol. % and less than or equal to 30.0 mol. %, a sum of FeO+Fe2O3 is greater than or equal to 0.000 mol. % and less than or equal to 0.020 mol. % and may optionally contain one or more components selected from Al2O3, B2O3, BaO, Bi2O3, CaO, CdO, Cs2O, GeO2, La2O3, MgO, MoO3, PbO, SiO2, SrO, Ta2O5, TeO2, WO3, ZrO2, Ga2O3 and ZnO, wherein the composition of the components is substantially free of V2O5, and wherein the composition of the components satisfies the conditions: P2O5/(TiO2+Nb2O5) [mol. %]≥0.30 and K2O−Na2O [mol. %]≥0.000, and the glass satisfies the conditions: Pn>1.9000 and Pd<3.80, where Pn is a refractive index parameter, calculated from the glass composition in terms of mol. % of the components according to the Formula (I):

Pd is a density parameter, calculated from the glass composition in terms of mol. % of the components according to the Formula (II):

where an asterisk (*) means multiplication.

According to a second aspect, the glass of the first aspect, wherein the glass has a refractive index at 587.56 nm, nd that is greater than or equal to 1.9000 and a density at room temperature, dRT that is less than or equal to 3.80 g/cm3.

According to a third aspect, the glass of any one of aspects 1-2, wherein the composition of the components comprises greater than or equal to 26.5 mol. % P2O5.

According to a fourth aspect, the glass of the third aspect, wherein the composition of the components comprises greater than or equal to 27.5 mol. % P2O5.

According to a fifth aspect, the glass of any one of aspects 1-4, wherein the composition of the components comprises less than or equal to 32.0 mol. % P2O5.

According to a sixth aspect, the glass of the fifth aspect, wherein the composition of the components comprises less than or equal to 30.0 mol. % P2O5.

According to a seventh aspect, the glass of any one of aspects 1-6, wherein the composition of the components comprises greater than or equal to 13.0 mol. % TiO2.

According to an eighth aspect, the glass of the seventh aspect, wherein the composition of the components comprises greater than or equal to 17.0 mol. % TiO2.

According to a ninth aspect, the glass of the eighth aspect, wherein the composition of the components comprises greater than or equal to 21.0 mol. % TiO2.

According to a tenth aspect, the glass of the ninth aspect, wherein the composition of the components comprises greater than or equal to 25.0 mol. % TiO2.

According to an eleventh aspect, the glass of the tenth aspect, wherein the composition of the components comprises greater than or equal to 29.0 mol. % TiO2.

According to a twelfth aspect, the glass of any one of aspects 1-11, wherein the composition of the components comprises less than or equal to 36.0 mol. % TiO2.

According to a thirteenth aspect, the glass of the twelfth aspect, wherein the composition of the components comprises greater than or equal to 32.0 mol. % TiO2.

According to a fourteenth aspect, the glass of the thirteenth aspect, wherein the composition of the components comprises less than or equal to 24.0 mol. % TiO2.

According to a fifteenth aspect, the glass of the fourteenth aspect, wherein the composition of the components comprises less than or equal to 22.5 mol. % TiO2.

According to a sixteenth aspect, the glass of the fifteenth aspect, wherein the composition of the components comprises less than or equal to 20.0 mol. % TiO2.

According to a seventeenth aspect, the glass of any one of aspects 1-16, wherein the composition of the components comprises greater than or equal to 18.0 mol. % and less than or equal to 23.5 mol. % TiO2.

According to a eighteenth aspect, the glass of any one of aspects 1-17, wherein the composition of the components comprises greater than or equal to 24.0 mol. % Nb2O5.

According to a nineteenth aspect, the glass of the eighteenth aspect, wherein the composition of the components comprises greater than or equal to 28.0 mol. % Nb2O5.

According to a twentieth aspect, the glass of the nineteenth aspect, wherein the composition of the components comprises greater than or equal to 30.0 mol. % Nb2O5.

According to a twenty-first aspect, the glass of the twentieth aspect, wherein the composition of the components comprises greater than or equal to 32.0 mol. % Nb2O5.

According to a twenty-second aspect, the glass of any one of aspects 1-21, wherein the composition of the components comprises less than or equal to 44.0 mol. % Nb2O5.

According to a twenty-third aspect, the glass of the twenty-second aspect, wherein the composition of the components comprises less than or equal to 40.0 mol. % Nb2O5.

According to a twenty-fourth aspect, the glass of the twenty-third aspect, wherein the composition of the components comprises less than or equal to 36.0 mol. % Nb2O5.

According to a twenty-fifth aspect, the glass of the twenty-fourth aspect, wherein the composition of the components comprises less than or equal to 35.0 mol. % Nb2O5.

According to a twenty-sixth aspect, the glass of the eighteenth aspect, wherein the composition of the components comprises greater than or equal to 28.0 mol. % and less than or equal to 35.0 mol. % Nb2O5.

According to a twenty-seventh aspect, the glass of any one of aspects 1-26, wherein the composition of the components comprises a sum of Li2O+Na2O+K2O greater than or equal to 10.0 mol. %.

According to a twenty-eighth aspect, the glass of the twenty-seventh aspect, wherein the composition of the components comprises a sum of Li2O+Na2O+K2O greater than or equal to 15.0 mol. %.

According to a twenty-ninth aspect, the glass of any one of aspects 1-28, wherein the composition of the components comprises a sum of Li2O+Na2O+K2O less than or equal to 25.0 mol. %.

According to a thirtieth aspect, the glass of the twenty-ninth aspect, wherein the composition of the components comprises a sum of Li2O+Na2O+K2O less than or equal to 20.0 mol. %.

According to a thirty-first aspect, the glass of the twenty-seventh aspect, wherein the composition of the components comprises a sum of Li2O+Na2O+K2O greater than or equal to 15.0 mol. % and less than or equal to 20.0 mol. %.

According to a thirty-second aspect, the glass of any one of aspects 1-31, wherein the composition of the components comprises two or more of Li2O, Na2O and K2O.

According to a thirty-third aspect, the glass of any one of aspects 1-32, wherein the composition of the components comprises greater than or equal to 5.0 mol. % K2O.

According to a thirty-fourth aspect, the glass of the thirty-third aspect, wherein the composition of the components comprises greater than or equal to 10.0 mol. % K2O.

According to a thirty-fifth aspect, the glass of any one of aspects 1-34, wherein the composition of the components comprises greater than or equal to 1.5 mol. % Li2O.

According to a thirty-sixth aspect, the glass of any one of aspects 1-35, wherein the composition of the components comprises less than or equal to 5.0 mol. % Li2O.

According to a thirty-seventh aspect, the glass of the thirty-sixth aspect, wherein the composition of the components comprises less than or equal to 3.0 mol. % Li2O.

According to a thirty-eighth aspect, the glass of any one of aspects 1-37, wherein the composition of the components comprises greater than or equal to 1.5 mol. % and less than or equal to 3.0 mol. % Li2O.

According to a thirty-ninth aspect, the glass of any one of aspects 1-38, wherein the composition of the components comprises greater than or equal to 0.0 mol. % and less than or equal to 2.0 mol. % Na2O.

According to a fortieth aspect, the glass of the thirty-ninth aspect, wherein the composition of the components comprises greater than or equal to 0.0 mol. % and less than or equal to 0.5 mol. % Na2O.

According to a forty-first aspect, the glass of the fortieth aspect, wherein the composition of the components is substantially free of Na2O.

According to a forty-second aspect, the glass of any one of aspects 1-41, wherein the composition of the components satisfies the conditions: K2O−Na2O [mol. %]≥0.50 and Li2O−Na2O [mol. %]≥0.50.

According to a forty-third aspect, the glass of the forty-second aspect, wherein the composition of the components satisfies the conditions: K2O−Na2O [mol. %]≥1.50 and Li2O−Na2O [mol. %]≥1.00.

According to a forty-fourth aspect, the glass of the forty-third aspect, wherein the composition of the components satisfies the conditions: K2O−Na20 [mol. %]≥3.00 and Li2O−Na2O [mol. %]≥1.50.

According to a forty-fifth aspect, the glass of any one of aspects 1-44, wherein the composition of the components comprises a sum of CaO+SrO+BaO greater than or equal to 3.0 mol. %.

According to a forty-sixth aspect, the glass of the forty-fifth aspect, wherein the composition of the components comprises a sum of CaO+SrO+BaO greater than or equal to 6.0 mol. %.

According to a forty-seventh aspect, the glass of any one of aspects 1-45, wherein the composition of the components comprises a sum of CaO+SrO+BaO less than or equal to 12.0 mol. %.

According to a forty-eighth aspect, the glass of the forty-seventh aspect, wherein the composition of the components comprises a sum of CaO+SrO+BaO less than or equal to 9.0 mol. %.

According to a forty-ninth aspect, the glass of the forty-eighth aspect, wherein the composition of the components comprises a sum of CaO+SrO+BaO greater than or equal to 6.0 mol. % and less than or equal to 9.0 mol. %.

According to a fiftieth aspect, the glass of any one of aspects 1-49, wherein the composition of the components comprises greater than or equal to 25.5 mol. % and less than or equal to 29.0 mol. % P2O5, greater than or equal to 20.0 mol. % and less than or equal to 35.0 mol. % Nb2O5, greater than or equal to 10.0 mol. % and less than or equal to 40.0 mol. % TiO2, greater than or equal to 5.0 mol. % and less than or equal to 15.0 mol. % K2O, greater than or equal to 1.0 mol. % and less than or equal to 2.5 mol. % Li2O, greater than or equal to 0.0 mol. % and less than or equal to 10.0 mol. % BaO and greater than or equal to 0.0 mol. % and less than or equal to 2.0 mol. % ZnO.

According to a fifty-first aspect, the glass of any one of aspects 1-50, wherein the composition of the components comprises one or more of the following: greater than or equal to 26.2 mol. % and less than or equal to 29.0 mol. % P2O5, greater than or equal to 22.0 mol. % and less than or equal to 33.0 mol. % Nb2O5, greater than or equal to 21.5 mol. % and less than or equal to 34.5 mol. % TiO2, greater than or equal to 6.0 mol. % and less than or equal to 14.0 mol. % K2O, greater than or equal to 1.1 mol. % and less than or equal to 2.3 mol. % Li2O, greater than or equal to 0.0 mol. % and less than or equal to 8.5 mol. % BaO and greater than or equal to 0.0 mol. % and less than or equal to 1.8 mol. % ZnO.

According to a fifty-second aspect, the glass of any one of aspects 1-52, wherein the composition of the components comprises greater than or equal to 26.5 mol. % and less than or equal to 28.4 mol. % P2O5, greater than or equal to 23.0 mol. % and less than or equal to 30.0 mol. % Nb2O5, greater than or equal to 21.5 mol. % and less than or equal to 33.0 mol. % TiO2, greater than or equal to 6.75 mol. % and less than or equal to 13.25 mol. % K2O, greater than or equal to 1.50 mol. % and less than or equal to 7.75 mol. % BaO, greater than or equal to 1.25 mol. % and less than or equal to 2.15 mol. % Li2O and greater than or equal to 0.0 mol. % and less than or equal to 1.6 mol. % ZnO.

According to a fifty-third aspect, the glass of the fiftieth aspect, wherein the composition of the components comprises greater than or equal to 26.0 mol. % and less than or equal to 32.0 mol. % P2O5, greater than or equal to 20.0 mol. % and less than or equal to 42.0 mol. % Nb2O5, greater than or equal to 13.0 mol. % and less than or equal to 38.4 mol. % TiO2, greater than or equal to 2.00 mol. % and less than or equal to 15.0 mol. % K2O, greater than or equal to 0.00 mol. % and less than or equal to 11.00 mol. % BaO, greater than or equal to 1.00 mol. % and less than or equal to 5.00 mol. % Li2O and greater than or equal to 0.0 mol. % and less than or equal to 2.0 mol. % Na2O.

According to a fifty-fourth aspect, the glass of any one of aspects 1-53, wherein the composition of the components comprises greater than or equal to 0.000 mol. % and less than or equal to 0.020 mol. % Cr2O3, and wherein the composition of the components is substantially free of B2O3, substantially free of Na2O, substantially free of SiO2, and substantially free of ZnO.

According to a fifty-fifth aspect, the glass of any one of aspects 1-54, wherein the composition of the components satisfies the condition: P2O5/(TiO2+Nb2O5) [mol. %]≥0.45.

According to a fifty-sixth aspect, the glass of the fifty-fifth aspect, wherein the composition of the components satisfies the condition: P2O5/(TiO2+Nb2O5) [mol. %]≥0.47.

According to a fifty-seventh aspect, the glass of the fifty-sixth aspect, wherein the composition of the components satisfies the condition: P2O5/(TiO2+Nb2O5) [mol. %]≥0.49.

According to a fifty-eighth aspect, the glass of the fifty-seventh aspect, wherein the composition of the components satisfies the condition: P2O5/(TiO2+Nb2O5) [mol. %]≥0.51.

According to a fifty-ninth aspect, the glass of the fifty-eighth aspect, wherein the composition of the components satisfies the condition: P2O5/(TiO2+Nb2O5) [mol. %]≥0.53.

According to a sixtieth aspect, the glass of any one of aspects 1-59, wherein the glass satisfies the condition: Pn>1.9300.

According to a sixty-first aspect, the glass of any one of aspects 1-60, wherein the glass has a refractive index at 587.56 nm, nd that is greater than or equal to 1.9300.

According to a sixty-second aspect, the glass of the sixty-first aspect, wherein the glass has a refractive index at 587.56 nm, nd that is greater than or equal to 1.9550.

According to a sixty-third aspect, the glass of any one of aspects 1-62, wherein the glass satisfies the condition: Pd<3.70.

According to a sixty-fourth aspect, the glass of the sixty-third aspect, wherein the glass satisfies the condition: Pd<3.60.

According to a sixty-fifth aspect, the glass of the sixty-fourth aspect, wherein the glass satisfies the condition: Pd<3.50.

According to a sixty-sixth aspect, the glass of any one of aspects 1-65, wherein the glass has a density at room temperature, dRT that is less than or equal to 3.70 g/cm3.

According to a sixty-seventh aspect, the glass of the sixty-sixth aspect, wherein the glass has a density at room temperature, dRT that is less than or equal to 3.60 g/cm3.

According to a sixty-eighth aspect, the glass of the sixty-seventh aspect, wherein the glass has a density at room temperature, dRT that is less than or equal to 3.50 g/cm3.

According to a sixty-ninth aspect, the glass of any one of aspects 1-68, wherein the glass satisfies the condition: Pref>0.24, where Pref is a refraction parameter, calculated from the glass composition in terms of mol. % of the components according to the Formula (IV):

where an asterisk (*) means multiplication.

According to a seventieth aspect, the glass of any one of aspects 1-69, wherein the glass has a refractive index to density ratio (“refraction”), (nd−1)/dRT that is greater than or equal to 0.24.

According to a seventy-first aspect, the glass of the seventieth aspect, wherein the glass has a refractive index to density ratio (“refraction”), (nd−1)/dRT that is greater than or equal to 0.25.

According to a seventy-second aspect, the glass of any one of aspects 1-71, wherein the glass satisfies the condition: Pν<18.50, where Pν is a dispersion parameter, calculated from the glass composition in terms of mol. % of the components according to the Formula (III):

where an asterisk (*) means multiplication.

According to a seventy-third aspect, the glass of any one of aspects 1-72, wherein the glass has an Abbe number, νd that is less than or equal to 18.50.

According to a seventy-fourth aspect, the glass of the seventy-third aspect, wherein the glass has an Abbe number, νd that is less than or equal to 18.25.

According to a seventy-fifth aspect, the glass of the seventy-fourth aspect, wherein the glass has an Abbe number, νd that is less than or equal to 18.00.

According to a seventy-sixth aspect, the glass of the seventy-fifth aspect, wherein the glass has an Abbe number, νd that is less than or equal to 17.75.

According to a seventy-seventh aspect, the glass of any one of aspects 1-76, wherein the glass has a liquidus temperature, Tliq that is less than or equal to 1125° C.

According to a seventy-eighth aspect, the glass of the seventy-seventh aspect, wherein the glass has a liquidus temperature, Tliq that is less than or equal to 1100° C.

According to a seventy-ninth aspect, the glass of the seventy-eighth aspect, wherein the glass has a liquidus temperature, Tliq that is less than or equal to 1075° C.

According to a eightieth aspect, the glass of any one of aspects 1-79, wherein the glass has a glass transition temperature, Tg that is greater than or equal to 620° C.

According to an eighty-first aspect, the glass of the eightieth aspect, wherein the glass has a glass transition temperature, Tg that is greater than or equal to 640° C.

According to an eighty-second aspect, the glass of the eighty-first aspect, wherein the glass has a glass transition temperature, Tg that is greater than or equal to 650° C.

According to an eighty-third aspect, a method for manufacturing an optical element, the method comprising processing a glass, wherein the glass is the glass of any one of aspects 1-82.

According to an eighty-fourth aspect, an optical element comprising a glass, wherein the glass is the glass of any one of aspects 1-83.

Many variations and modifications may be made to the above-described embodiments of the disclosure without departing substantially from the spirit and various principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

To the extent not already described, the different features of the various aspects of the present disclosure may be used in combination with each other as desired. That a particular feature is not explicitly illustrated or described with respect to each aspect of the present disclosure is not meant to be construed that it cannot be, but it is done for the sake of brevity and conciseness of the description. Thus, the various features of the different aspects may be mixed and matched as desired to form new aspects, whether or not the new aspects are expressly disclosed.