Ultraviolet blocking glass composition for space applications

Abstract

This invention discloses a glass composition comprising: 65-79 mol% SiO2; 4-13.5 mol% Al2O3; 1.5-4.0 mol% MgO; 1-4 mol% CaO; 0-1.5 mol% ZnO; 4-16 mol% Na2O; 0-5.5 mol% K2O; 0.4-2.5 mol% TiO2; and 0-1.5 mol% CeO2. The glass composition, at a thickness of 50 µm, exhibits a transmittance percentage of 50% in the ultraviolet (UV) wavelength range of 320 nm to 350 nm, and / or a coefficient of thermal expansion (CTE) of 69 × 10⁻⁶ measured at 100°C to 300°C. ‑7 / ℃ to 75 × 10 ‑7 / ℃.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 547,792, filed November 8, 2023, pursuant to 35 USC § 119, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates to glass compositions and articles having UV-blocking properties, and more specifically, UV-blocking glass compositions and articles for a variety of applications, including photovoltaic (PV) cells for terrestrial and space applications. Background Technology

[0004] Currently, glass is required as a cover material for solar panels on satellites in aerospace applications. Conventional glass compositions used in these applications do not block sufficient ultraviolet (UV) light, and the solar panels on these satellites may experience significant degradation. Furthermore, conventional glass compositions are susceptible to radiation damage, thus limiting their ability to protect the solar panels used in satellite applications. Specifically, radiation damage can cause fading and darkening over time, reducing the transmittance and solar energy efficiency of these panels.

[0005] Other historical glass compositions used in these applications are no longer in production. These historical glass compositions employed unoptimized solutions to achieve the desired absorption levels. For example, these compositions required significant amounts of cerium (up to 5 wt%) for radiation protection, and cerium is an expensive raw material.

[0006] Solar panels used in current space (extraterrestrial) applications can benefit from novel thin glass compositions capable of blocking UV radiation in the 300-350 nm range to a maximum of 50% transmittance. Thin glass is necessary because launching additional weight into orbit incurs astronomical costs. Furthermore, the novel cover glass compositions used in solar panels should preferably exhibit a coefficient of thermal expansion (CTE) that matches, as closely as possible, the historical and conventional glass compositions previously and currently used in such applications to avoid the costs of system redesign (e.g., associating with materials with different CTEs to accommodate novel cover glasses with different CTEs).

[0007] Therefore, there is a need for novel glass compositions and articles with UV-blocking properties, and more specifically, UV-blocking glass compositions and articles for a variety of applications, including photovoltaic (PV) cells for terrestrial and space applications. Preferably, the CTE of these compositions at 100°C to 300°C should be substantially compatible with that of conventional glass compositions used in space (e.g., about 7 × 10⁻⁶).-6 The composition can be produced at a lower cost and with a smaller thickness (approximately 50 µm), thus supporting low launch costs. Summary of the Invention

[0008] According to one aspect of this disclosure, a glass composition is provided, the glass composition comprising:

[0009] Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2;

[0010] Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3;

[0011] MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%;

[0012] Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO;

[0013] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO;

[0014] Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O;

[0015] Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O;

[0016] Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and

[0017] CeO2, greater than or equal to 0 mol% to less than or equal to 1.5 mol%.

[0018] According to one aspect of this disclosure, a glass composition is provided, the glass composition comprising:

[0019] Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2;

[0020] Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3;

[0021] MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%;

[0022] Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO;

[0023] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO;

[0024] Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O;

[0025] Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O;

[0026] Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and

[0027] CeO2, greater than or equal to 0 mol% to less than or equal to 1.5 mol%.

[0028] In addition, the glass composition has a transmittance percentage of 50% in the ultraviolet wavelength (UV) range of 320 nm to 350 nm at a thickness of 50 µm.

[0029] According to one aspect of this disclosure, a glass composition is provided, the glass composition comprising:

[0030] Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2;

[0031] Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3;

[0032] MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%;

[0033] Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO;

[0034] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO;

[0035] Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O;

[0036] Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O;

[0037] Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and

[0038] CeO2, greater than or equal to 0 mol% to less than or equal to 1.5 mol%.

[0039] The glass composition, with a thickness of 50 µm, exhibits a 50% transmittance percentage in the ultraviolet (UV) wavelength range of 320 nm to 350 nm. Furthermore, the coefficient of thermal expansion (CTE) of the glass composition, measured at temperatures ranging from 100°C to 300°C, is 69 × 10⁻⁶.-7 / ℃ to 75 × 10 -7 / ℃.

[0040] Additional features and advantages will be set forth in the detailed description below, and will be apparent in part from the description or by practice of the embodiments described herein, including the following detailed description, the claims and the drawings.

[0041] It should be understood that both the foregoing general description and the following detailed description are merely exemplary and are intended to provide an overview or framework for understanding the nature and characteristics of this disclosure and the appended claims.

[0042] The accompanying drawings are included to provide further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, by way of example, are used together with the specification to explain the principles and operation of this disclosure. It should be understood that the various features of this disclosure disclosed in this specification and the drawings can be used in any and all combinations. By way of non-limiting example, the various features of this disclosure can be combined with each other according to the following embodiments. Attached Figure Description

[0043] Figure 1A This is an outdated plot comparing the transmittance (%) of UV-blocking glass and Corning® Willow® glass against the optical spectrum (visible and ultraviolet).

[0044] Figure 1B This is a schematic diagram showing how the efficiency degradation (%) of photovoltaic (PV) cells changes over time (years) for terrestrial and space applications;

[0045] Figure 2 This is a plot of the transmittance (%) of comparative and example glass compositions according to one or more embodiments of the present disclosure against the UV (ultraviolet) spectrum;

[0046] Figures 3A-3C This is a plot of the transmittance (%) of an example glass composition according to one or more embodiments of the present disclosure against the UV spectrum;

[0047] Figure 4 This is a plot of glass removal depth (µm) versus time (minutes) for etching example glass compositions according to one or more embodiments of this disclosure; and

[0048] Figure 5 These are photographs of example glass compositions irradiated by unirradiation and by X-ray fluorescence (XRF) spectroscopy according to one or more embodiments of this disclosure. Detailed Implementation

[0049] In the following detailed description, exemplary embodiments with specific details disclosed are set forth for purposes of explanation and not limitation to provide a thorough understanding of the various principles of this disclosure. However, it will be apparent to those skilled in the art who will benefit from this disclosure that this disclosure may be practiced in other embodiments that depart from the specific details disclosed herein. Furthermore, descriptions of well-known apparatuses, methods, and materials may be omitted to avoid obscuring the description of the various principles of this disclosure. Finally, wherever applicable, the same reference numerals refer to the same elements.

[0050] In this document, a range may be expressed as from “about” a specific value and / or to “about” another specific value. Another embodiment of expressing such a range includes from one specific value and / or to another specific value. Similarly, when a value is expressed as an approximation using the antecedent “about,” it should be understood that a specific value forms another embodiment. It should be further understood that each endpoint of a range is meaningful both relative to and independent of the other endpoint.

[0051] Unless otherwise expressly stated, it is not intended to interpret any method set forth herein as requiring its steps to be performed in a particular order. Therefore, no inference is made in any respect of the order in which the method claims actually describe the order of their steps or that the steps should be limited to a particular order unless otherwise specifically stated in the claims or description. This applies to any possible non-expressive basis for interpretation, including: logical questions relating to the arrangement of steps or the flow of operations; simple meanings derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0052] As used herein, unless the context clearly indicates otherwise, the singular forms “a / an” and “the” include plural indicators. Thus, for example, unless the context clearly indicates otherwise, a reference to “component” includes aspects having two or more such components.

[0053] In the embodiments of the glass compositions described herein, unless otherwise specified, the concentrations of the constituent components (e.g., SiO2, Al2O3, etc.) are specified in mole percentage (mol%) as oxides.

[0054] The terms "0 mol%" and "substantially absent" when used to describe the concentration and / or absence of a particular constituent component in a glass composition mean that the constituent component was not intentionally added to the glass composition. However, the glass composition may contain trace amounts of the constituent component as contaminants or residues, in amounts less than 0.01 mol%.

[0055] As used herein, the terms “significant,” “substantially,” and variations thereof are intended to indicate that the described feature is equal to or approximately equal to a value or description. For example, a “substantially flat” surface is intended to mean a flat or substantially flat surface. Furthermore, “substantially” is intended to mean that two values ​​are equal or approximately equal. In some embodiments, “substantially” may mean values ​​that differ from each other by about 10%, such as values ​​that differ from each other by about 5%, or values ​​that differ from each other by about 2%.

[0056] As used herein, the terms “glass article” and “glass articles” are used in their broadest sense to include any object that is wholly or partially made of glass and / or glass ceramics.

[0057] Unless otherwise specified, all compositions are expressed as a mole percentage (mol%). The coefficient of thermal expansion (CTE) is expressed in terms of 10⁻⁶. -7 The value is expressed in the form of / ℃ and represents the value measured in the temperature range of about 100℃ to about 300℃ or about 100℃ to about 500℃, as specified.

[0058] As used herein, “transmission,” “transmittance,” “optical transmittance,” and “total transmittance” are used interchangeably in this disclosure and refer to external transmittance or transmittance that takes into account absorption, scattering, and reflection. Fresnel reflection is not excluded from the transmittance and transmittance values ​​reported herein. Furthermore, any total transmittance value referenced within a specific wavelength range (e.g., the visible spectrum from 400 nm to 700 nm, and the UV spectrum from 200 nm to 400 nm) is given as an average of the total transmittance values ​​measured within that specific wavelength range.

[0059] As described in this article, the viscosity of the glass composition was measured according to ASTM C965-96.

[0060] As used in this paper, the term “Vogel-Fulcher-Tamman ('VFT') relation” describes the temperature dependence of viscosity and is expressed by the following equation:

[0061]

[0062] Where α is viscosity. To determine VFT A, VFT B, and VFT T... o The viscosity of the glass composition was measured within a given temperature range. The raw viscosity versus temperature data were then fitted to the VFT equation using least-squares fitting to obtain A, B, and T. oUsing these values, the viscosity point at any temperature above the softening point can be calculated (e.g., 200 P, 35000 P, and 200000 P).

[0063] As used herein, the term “melting point” refers to the temperature at which the viscosity of a glass composition, as measured according to ASTM C338, is 200 poise.

[0064] As used herein, the term "softening point" refers to a glass composition with a viscosity of 1 × 10⁻⁶. 7.6 The softening point was measured at the temperature at which the material was poured. The softening point was determined using the parallel plate viscosity method, which measures the change in viscosity with temperature. 7 Up to 10 9 The viscosity of the inorganic glass is similar to that of ASTM C1351M.

[0065] As used herein, the term "annealing point" or "effective annealing temperature" refers to a glass composition with a viscosity of 1 × 10⁻⁶. 13.18 The temperature at which the glass composition is held. In an example, holding the glass composition at the effective annealing temperature of the glass composition ± 20°C for a period of greater than or equal to 15 minutes and less than or equal to 1 hour can relieve the internal stress present according to ASTM C598.

[0066] As used herein, the term "strain point" refers to the point at which the viscosity of the glass composition, as measured according to ASTM C598, is 1 × 10⁻⁶. 14.68 Temperature at the time of berthing.

[0067] As described in this article, density was measured using the buoyancy method according to ASTM C693-93.

[0068] As used herein, the term “liquidline viscosity” refers to the viscosity of a glass composition at the onset of crystallization (i.e., at the liquidus temperature determined by the gradient furnace method according to ASTM C829-81).

[0069] As used herein, the term “liquidline temperature” refers to the temperature at which a glass composition begins to crystallize, as determined by the gradient furnace method according to ASTM C829-81.

[0070] As described herein, the elastic modulus (also known as Young's modulus) of the glass composition is provided in gigapascals (GPa) and is measured according to ASTM C623. The shear modulus of the glass composition is also provided in gigapascals (GPa) and is measured according to ASTM C623. Additionally, Poisson's ratio is measured according to ASTM C623.

[0071] As described in this article, the refractive index was measured according to ASTM E1967.

[0072] As used in this article, the phrases “average heating rate” and “average cooling rate” are measured by dividing the total temperature change recorded by a thermocouple by the total time of heating or cooling, respectively.

[0073] Generally, this disclosure relates to glass compositions based on the soda-lime glass family, which provides UV-blocking properties. These glass compositions include TiO2, and may also include a small amount of CeO2, and can be produced in particularly thin forms (e.g., down to 50 µm) using a slot drawing apparatus. Furthermore, the CTE (Crystal Strength Equivalent) of these compositions at 100°C to 300°C is substantially comparable to that of conventional glass compositions used in space (e.g., about 7 × 10⁻⁶). -6 / ℃).

[0074] The advantages of the glass compositions disclosed herein include:

[0075] (a) Compared to conventional glass compositions in the field of this disclosure (e.g., Corning® Willow® glass, such as...) Figure 1A The UV blocking properties (shown and described below) are improved UV blocking;

[0076] (b) It can extend the lifespan of solar cells used in satellite applications;

[0077] (c) The CeO2 content is lower compared to historical glass compositions in the field of this disclosure (e.g., Comparative Example 1C, such as...). Figure 1A (as shown and described below)

[0078] (d) Damage caused by solar and space-related radiation can be mitigated by using a moderate amount of CeO2 (see...). Figure 1B (as described below)

[0079] (e) It can be manufactured using existing fusion drawing, slot drawing and float glass equipment;

[0080] (f) A CTE level that is substantially similar to the CTE levels of current and historical conventional glass compositions in the field of this disclosure; and

[0081] (f) It exhibits a transmittance level in the UV spectrum that is substantially similar to that of current and historical conventional glass compositions in the field of this disclosure, while also having a lower density level.

[0082] refer to Figure 1AThis paper provides a plot of transmittance (%) against the optical spectrum (visible and ultraviolet) for obsolete conventional UV-blocking glass (Comparative Example 1C, 150 µm thick, further described in the Examples section) and Corning® Willow® glass (200 µm thick). It is evident from the plot that Corning® Willow® glass (a conventional thin glass) does not provide significant UV blocking, as it exhibits a transmittance level greater than 85% in the 320 nm to 400 nm range. On the other hand, the obsolete conventional UV-blocking glass (Comparative Example 1C) does provide acceptable UV blocking; however, it has a high level of expensive CeO2 content and, furthermore, is unsuitable for production on existing slot drawing, fusion drawing, and float glass equipment.

[0083] Now for reference Figure 1B This provides a schematic diagram showing how the efficiency degradation (%) of photovoltaic (PV) cells changes over time (years) for terrestrial and space applications. It is evident from the diagram that conventional terrestrial PV cells using conventional cover glass compositions experience moderate degradation over a duration of approximately 5 years; while PV cells used in space (extraterrestrial) applications using conventional cover glass compositions experience significant degradation (>80%) over a duration of approximately 5 years.

[0084] The glass compositions disclosed herein exhibit one or more of the aforementioned advantages and overcome [the following limitations]. Figure 1A and 1B The problems outlined herein are addressed. Therefore, the glass compositions disclosed herein can be used in a wide range of applications, including, for example, UV blocking applications (e.g., PV and solar cells used in space and terrestrial applications), UV absorbing applications (e.g., cover plates, UV sterilization components, and / or tanning beds); cover glass or glass backplates in consumer or commercial electronic devices, including, for example, LCD and LED displays, computer monitors, and ATMs; touchscreen or touch sensor applications; portable electronic devices, including, for example, mobile phones, personal media players, and tablet computers; integrated circuit applications, including, for example, semiconductor wafers; photovoltaic applications; architectural glass applications; automotive or vehicle glass applications; or commercial or household appliance applications.

[0085] The glass compositions disclosed herein can be described as aluminoborosilicate glass compositions and comprise SiO2, Al2O3, B2O3, and UV-blocking components such as CeO2 and / or TiO2. In addition to SiO2, Al2O3, B2O3, and at least one UV-blocking component, the glass compositions embodied and described herein also include alkali oxides such as Na2O to achieve ion exchangeability of the glass compositions. More specifically, the glass compositions disclosed herein comprise: 65-79 mol% SiO2; 4-13.5 mol% Al2O3; 1.5-4.0 mol% MgO; 1-4 mol% CaO; 0-1.5 mol% ZnO; 4-16 mol% Na2O; 0-5.5 mol% K2O; 0.4-2.5 mol% TiO2; and 0-1.5 mol% CeO2. The glass composition exhibits a transmittance percentage of 50% at ultraviolet wavelengths (UV) in the range of 320 nm to 350 nm at a thickness of 50 µm, and / or a coefficient of thermal expansion (CTE) of 69 x 10⁻⁶ measured at 100 °C to 300 °C. -7 / ℃ to 75 x 10 -7 / ℃.

[0086] In all embodiments of this disclosure, at least some cerium (TiO2) is present as a UV absorber. In some embodiments, CeO2 is used in addition to TiO2. When Ce is used in combination with Ti, a lower Ce content is determined to be useful for achieving the desired UV blocking at or within the target UV wavelength range (while maintaining desired properties, including CTE levels comparable to conventional glass compositions, low density for panel weight reduction, and / or radiation resistance).

[0087] In embodiments, the glass composition comprises greater than or equal to 0.4 mol% and less than or equal to 2.5 mol% TiO2, greater than or equal to 1 mol% and less than or equal to 2.5 mol% TiO2, or greater than or equal to 1.9 mol% and less than or equal to 2.5 mol% TiO2. In embodiments, the glass composition may comprise greater than or equal to 0.6 mol% and less than or equal to 2.4 mol% TiO2, or greater than or equal to 0.8 mol% and less than or equal to 2.4 mol% TiO2. In the embodiments, the concentration of TiO2 in the glass composition can be greater than or equal to 0.4 mol%, greater than or equal to 0.5 mol%, greater than or equal to 0.6 mol%, greater than or equal to 0.7 mol%, greater than or equal to 0.8 mol%, greater than or equal to 0.9 mol%, greater than or equal to 1 mol%, greater than or equal to 1.2 mol%, greater than or equal to 1.4 mol%, greater than or equal to 1.6 mol%, greater than or equal to 1.8 mol%, greater than or equal to 2.0 mol%, or greater than or equal to 2.1 mol%. In the embodiments, the concentration of TiO2 in the glass composition can be less than or equal to 2.5 mol%, less than or equal to 2.4 mol%, less than or equal to 2.3 mol%, less than or equal to 2.2 mol%, less than or equal to 2.1 mol%, or even less than or equal to 2.0 mol%.

[0088] In embodiments, the glass composition may contain greater than or equal to 0 mol% and less than or equal to 1.5 mol% CeO2. In embodiments, the glass composition may contain greater than or equal to 0.1 mol% and less than or equal to 1.5 mol%, greater than or equal to 0.4 mol% and less than or equal to 1.2 mol% CeO2, or any and all subranges formed by any of these endpoints or between any endpoints. In embodiments, the concentration of CeO2 in the glass composition may be greater than or equal to 0.1 mol%, 0.2 mol%, 0.3 mol%, 0.4 mol%, 0.5 mol%, or even 0.6 mol%. In some embodiments, the concentration of CeO2 may be greater than or equal to 0.8 mol%, greater than or equal to 0.9 mol%, greater than or equal to 1.0 mol%, greater than or equal to 1.1 mol%, or even greater than or equal to 1.2 mol%. In the embodiments, the concentration of CeO2 in the glass composition may be less than or equal to 1.5 mol%, less than or equal to 1.4 mol%, less than or equal to 1.2 mol%, less than or equal to 1 mol%, less than or equal to 0.8 mol%, less than or equal to 0.6 mol%, or even less than or equal to 0.4 mol%.

[0089] SiO2 is the primary glass-forming agent in the glass compositions described herein and can be used to stabilize the network structure of the glass composition. In this field, a high concentration of SiO2 in the glass composition (e.g., greater than or equal to 65 mol%) is generally considered to provide basic glass-forming ability. The upper limit of the SiO2 content can be slightly limited (e.g., to less than or equal to 80 mol%) to control the melting point of the glass composition, as the melting temperature of pure SiO2 or high-SiO2 glasses may be undesirably high. Therefore, slightly limiting the SiO2 concentration can help improve the meltability and formability of the glass composition. Thus, in the embodiments, the glass composition may contain greater than or equal to 65 mol% and less than or equal to 79 mol% SiO2, greater than or equal to 66.7 mol% and less than or equal to 78.0 mol% SiO2, greater than or equal to 70 mol% and less than or equal to 79 mol% SiO2, greater than or equal to 71.6 mol% and less than or equal to 78.0 mol% SiO2, or any and all subranges formed by any of these endpoints. For example, SiO2 can be set to 65 mol%, 66 mol%, 67 mol%, 68 mol%, 69 mol%, 70 mol%, 71 mol%, 72 mol%, 73 mol%, 74 mol%, 75 mol%, 76 mol%, 77 mol%, 78 mol%, or 79 mol%, and all SiO2 levels are between the aforementioned values. In embodiments, the glass composition may contain greater than or equal to 67 mol% and less than or equal to 77 mol% SiO2. In embodiments, the glass composition may contain greater than or equal to 69 mol% and less than or equal to 76 mol% SiO2.

[0090] Similar to SiO2, Al2O3 can stabilize the glass network and additionally provide improved mechanical properties and chemical durability to the glass composition. The amount of Al2O3 can also be tailored to control the viscosity and / or phase separation of the glass composition. The concentration of Al2O3 should be sufficiently high (e.g., greater than or equal to 4 mol%) to allow for multiphase formation through phase separation. However, if the amount of Al2O3 is too high, the viscosity of the melt may increase, thereby reducing the formability of the glass composition. In examples, the glass composition may contain greater than or equal to 4 mol% and less than or equal to 13.5 mol% Al2O3. In examples, the glass composition may contain greater than or equal to 4.9 mol% and less than or equal to 12.6 mol% Al2O3. In examples, the glass composition may contain greater than or equal to 6 mol% and less than or equal to 11 mol% Al2O3. In the embodiments, the concentration of Al2O3 in the glass composition may be greater than or equal to 4 mol% and less than or equal to 13.5 mol%, greater than or equal to 4.9 mol% and less than or equal to 12.6 mol%, greater than or equal to 5 mol% and less than or equal to 12 mol%, or any and all subranges formed by any of these endpoints or between any endpoints.

[0091] Generally, the B2O3 content in the glass compositions of this disclosure is limited. If the B2O3 level is too high, chemical durability and liquidus viscosity may be affected, and evaporation during melting may be difficult to control. Therefore, the amount of B2O3 can be limited (e.g., less than or equal to 2 mol%, 1.5 mol%, or 1 mol%) to maintain the chemical durability and manufacturability of the glass composition. In other embodiments, the glass compositions of this disclosure are substantially free of B2O3.

[0092] As described above, the glass composition may contain alkali oxides, such as Na₂O, to achieve ion exchangeability. In addition to contributing to ion exchangeability, Na₂O also lowers the melting point and improves the formability of the glass composition. However, if too much Na₂O is added to the glass composition, the melting point may be too low. In embodiments, the glass composition may contain greater than or equal to 4 mol% and less than or equal to 16 mol% Na₂O. In embodiments, the concentration of Na₂O in the glass composition may be greater than or equal to 4 mol%, greater than or equal to 6 mol%, greater than or equal to 8 mol%, or even greater than or equal to 10 mol%. In embodiments, the concentration of Na₂O in the glass composition may be less than or equal to 16 mol%, less than or equal to 14 mol%, less than or equal to 12 mol%, less than or equal to 10 mol%, or even less than or equal to 8 mol%. In the embodiments, the concentration of Na2O in the glass composition may be greater than or equal to 4 mol% and less than or equal to 16 mol%, greater than or equal to 5.1 mol% and less than or equal to 15 mol%, greater than or equal to 6 mol% and less than or equal to 14 mol%, greater than or equal to 7 mol% and less than or equal to 13 mol%, or any and all subranges formed by any of these endpoints or between any endpoints.

[0093] The glass compositions described herein may also contain alkali metal oxides other than Na₂O, such as K₂O. K₂O can promote ion exchange to increase the depth of compression and lower the melting point, thereby improving the formability of the glass composition. However, the addition of K₂O may result in excessively low surface compressive stress and melting point. In embodiments, the concentration of K₂O in the glass composition may be greater than or equal to 0 mol% to no greater than or equal to 5.5 mol%. In some embodiments, at least some K₂O (e.g., > 0 mol%) is present, up to no greater than 5.5 mol%, or any and all subranges formed by any of these endpoints. In some embodiments, the concentration of K₂O in the glass composition may be greater than or equal to 0 mol% and less than or equal to 5.5 mol%, greater than or equal to 0 mol% and less than or equal to 4.6 mol%, greater than or equal to 0.1 mol% and less than or equal to 4 mol%, greater than or equal to 0.1 mol% and less than or equal to 3 mol%, or any and all subranges formed by any of these endpoints or between any of these endpoints.

[0094] The glass compositions described herein typically contain MgO. MgO can reduce the viscosity of the glass composition, thereby enhancing its formability, strain point, and Young's modulus, and can further improve its ion exchangeability. However, when excessive MgO is added to the glass composition, the diffusion rates of sodium and potassium ions in the glass composition may be significantly reduced, which in turn adversely affects the ion exchange properties (i.e., the ion exchange capacity) of the resulting glass. In the examples, the concentration of MgO in the glass composition may be greater than or equal to 1.5 mol%, greater than or equal to 1.75 mol%, greater than or equal to 2 mol%, or even greater than or equal to 2.5 mol%. In the examples, the concentration of MgO in the glass composition may be less than or equal to 4.0 mol%, less than or equal to 3.5 mol%, less than or equal to 3 mol%, or even less than or equal to 2.5 mol%.

[0095] In some embodiments, the concentration of MgO in the glass composition is greater than or equal to 1.5 mol% and not greater than 4.0 mol%, including any and all subranges formed by or between these endpoints. In some embodiments, the concentration of MgO in the glass composition is greater than or equal to 2.3 mol% and not greater than 3.2 mol%, including any and all subranges formed by or between these endpoints. In some embodiments, the concentration of MgO in the glass composition is greater than or equal to 1.5 mol% and less than or equal to 4.0 mol%, greater than or equal to 2 mol% and less than or equal to 3.5 mol%, or greater than or equal to 2.3 mol% and less than or equal to 3.2 mol%, including any and all subranges formed by or between any of these endpoints.

[0096] The glass compositions described herein typically contain CaO. CaO can reduce the viscosity of the glass composition, thereby enhancing its formability, strain point, and Young's modulus, and can also improve its ion exchangeability. However, when excessive CaO is added to the glass composition, the diffusion rate of sodium and potassium ions in the glass composition decreases, which in turn adversely affects the ion exchange properties (i.e., the ion exchange capacity) of the resulting glass. In embodiments, the glass composition may contain greater than or equal to 1 mol% and less than or equal to 4 mol% CaO, including any and all subranges formed by or between these endpoints. In embodiments, the glass composition may contain greater than or equal to 1.2 mol% and less than or equal to 3.4 mol% CaO or greater than or equal to 1.8 mol% and less than or equal to 3.4 mol% CaO, including any and all subranges formed by or between these endpoints.

[0097] In the embodiments, the concentration of CaO in the glass composition may be greater than or equal to 1 mol%, greater than or equal to 1.25 mol%, greater than or equal to 1.5 mol%, or even greater than or equal to 2 mol%. In the embodiments, the concentration of CaO in the glass composition may be less than or equal to 4 mol%, less than or equal to 3.5 mol%, less than or equal to 3 mol%, or even less than or equal to 2.5 mol%.

[0098] Generally, ZnO levels are limited in the glass compositions of this disclosure. Nevertheless, adding a limited amount of ZnO can promote or adjust a desired CTE value, thereby benefiting the glass compositions of this disclosure. In some embodiments, including ZnO can replace other alkaline earth oxides to improve the liquidus temperature and / or improve the UV light blocking properties of the composition. Therefore, ZnO may be included, but may be limited, for example, less than or equal to 1.5 mol%, less than or equal to 1.25 mol%, or even less than or equal to 1 mol%. In other embodiments, the glass compositions of this disclosure are substantially ZnO-free.

[0099] In embodiments, the glass compositions described herein may include one or more clarifying agents. Advantageously, glass compositions of this disclosure having a CeO2 content may not require any additional clarifying agent, as CeO2 itself can serve this purpose. In other embodiments, the clarifying agent may include, for example, SnO2. In some embodiments, for example, the concentration of SnO2 in the glass composition may be greater than or equal to 0 mol%. In embodiments, the concentration of SnO2 in the glass composition may be less than or equal to 0.18 mol%, less than or equal to 0.16 mol%, less than or equal to 0.14 mol%, less than or equal to 0.12 mol%, less than or equal to 0.1 mol%, less than or equal to 0.05 mol%, or even less than or equal to 0.01 mol%. In embodiments, the concentration of SnO2 in the glass composition can be greater than or equal to 0 mol% and less than or equal to 0.18 mol%, greater than or equal to 0 mol% and less than or equal to 0.15 mol%, greater than or equal to 0 mol% and less than or equal to 0.1 mol%, greater than or equal to 0 mol% and less than or equal to 0.05 mol%, greater than or equal to 0 mol% and less than or equal to 0.01 mol%, or any and all subranges formed by any of these endpoints or between any endpoints. In some embodiments, the concentration of SnO2 can range from 0.1 mol% to 0.18 mol% or from 0.12 mol% to 0.16 mol%. However, in other embodiments, the glass composition may be substantially SnO2-free.

[0100] In the embodiments, the glass composition described herein may also include residual materials such as Fe2O3, MnO, MoO3, La2O3, CdO, As2O3, Sb2O3, sulfur-based compounds such as sulfates, halogens, or combinations thereof.

[0101] According to one embodiment of the present disclosure, the glass composition comprises:

[0102] Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2;

[0103] Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3;

[0104] MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%;

[0105] Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO;

[0106] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO;

[0107] Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O;

[0108] Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O;

[0109] Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and

[0110] CeO2, greater than or equal to 0 mol% to less than or equal to 1.5 mol%.

[0111] According to another embodiment of this disclosure, the glass composition comprises:

[0112] Greater than or equal to 66.7 mol% to less than or equal to 78.0 mol% SiO2;

[0113] Greater than or equal to 4.9 mol% to less than or equal to 12.6 mol% Al2O3;

[0114] MgO concentration greater than or equal to 2.3 mol% to less than or equal to 3.2 mol%;

[0115] Greater than or equal to 1.2 mol% to less than or equal to 3.4 mol% CaO;

[0116] Greater than or equal to 0 mol% to less than or equal to 1.0 mol% ZnO;

[0117] Greater than or equal to 5.1 mol% to less than or equal to 15.0 mol% Na2O;

[0118] Greater than or equal to 0 mol% to less than or equal to 4.6 mol% K2O;

[0119] Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2;

[0120] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% CeO2; and

[0121] Greater than or equal to 0.1 mol% to less than or equal to 0.18 mol% SnO2.

[0122] Articles formed from the glass compositions described in this disclosure can be of any suitable shape or thickness, which may vary depending on the specific application in which the glass composition is used. The thickness of the glass plate embodiments may be greater than or equal to 10 µm, greater than or equal to 15 µm, greater than or equal to 20 µm, or even greater than or equal to 25 µm. In embodiments, the thickness of the glass plate embodiments may be less than or equal to 250 µm, less than or equal to 200 µm, less than or equal to 150 µm, or even less than or equal to 100 µm. Therefore, the thickness of articles formed from the glass compositions of this disclosure can be 10 µm, 12.5 µm, 15 µm, 17.5 µm, 20 µm, 25 µm, 30 µm, 35 µm, 40 µm, 45 µm, 50 µm, 55 µm, 60 µm, 65 µm, 70 µm, 75 µm, 80 µm, 85 µm, 90 µm, 95 µm, 100 µm, 125 µm, 150 µm, 175 µm, 200 µm, 225 µm, 250 µm, and all thickness values ​​between the aforementioned thicknesses.

[0123] In the embodiments, the density of the glass composition may be greater than or equal to 2.35 g / cm³. 3 ≥2.40 g / cm 3 Or even greater than or equal to 2.45 g / cm³ 3 In the embodiments, the density of the glass composition may be less than or equal to 2.5 g / cm³. 3 Less than or equal to 2.47 g / cm³ 3 Or even less than or equal to 2.45 g / cm³ 3 In the embodiments, the density of the glass composition may be greater than or equal to 2.35 g / cm³. 3 And less than or equal to 2.5 g / cm 3≥2.35 g / cm 3 And less than or equal to 2.45 g / cm³ 3 , or any and all subranges formed by any of these endpoints.

[0124] According to some embodiments, the glass composition of this disclosure can exhibit a CTE substantially matching that of a material used in a solar panel, where the glass composition serves as a protective cover. The CTE of the glass composition of this disclosure, measured at 100°C to 300°C, can range from 69 × 10⁻⁶. -7 / ℃ to 75 × 10 -7 / ℃, 71 × 10 -7 / ℃ to 75 × 10 -7 / ℃ or 72 × 10 -7 / ℃ to 74 × 10 -7 / ℃. For example, the CTE of the glass composition of this disclosure, measured at 100℃ to 300℃, can be 69 × 10⁻⁶. -7 / ℃, 69.5 × 10 -7 / ℃, 70 × 10 -7 / ℃, 70.5 × 10 -7 / ℃, 71 × 10 -7 / ℃, 71.5 × 10 -7 / ℃, 72 × 10 -7 / ℃, 72.5 × 10 -7 / ℃, 73 × 10 -7 / ℃, 73.5 × 10 -7 / ℃, 74 × 10 -7 / ℃, 74.5 × 10 -7 / ℃, 75 × 10 -7 / ℃, and any CTE value between the aforementioned values.

[0125] The glass compositions of this disclosure typically exhibit a 50% transmittance cutoff point in the UV wavelength range (e.g., 200 nm to 400 nm), as measured at a thickness of 50 µm. That is, the glass compositions of this disclosure may exhibit a transmittance level of less than or equal to 50% in the UV wavelength range (e.g., 200 nm to 400 nm), as measured at a thickness of 50 µm. In some embodiments, the glass compositions of this disclosure exhibit a 50% transmittance cutoff point in the range of 320 to 350 nm, as measured in an article having a composition with a thickness of 50 µm. In some embodiments, the glass compositions of this disclosure may exhibit a 50% transmittance cutoff point in the range of 340 nm to 350 nm at an article thickness of 50 µm. For example, the glass compositions disclosed herein can exhibit a 50% transmittance cutoff at UV wavelengths of 300 nm, 305 nm, 310 nm, 315 nm, 320 nm, 325 nm, 330 nm, 335 nm, 340 nm, 345 nm, or even 350 nm, and at all wavelengths between the aforementioned wavelengths, as measured at an article thickness of 50 µm.

[0126] According to some embodiments, the glass compositions of this disclosure are relatively easy to manufacture on existing glass forming equipment (e.g., slot drawing, fusion drawing, and float glass equipment). In some embodiments, the liquidus temperature exhibited by the glass compositions of this disclosure can be below 1125°C, below 1115°C, or even below 1100°C, as measured internally in a gradient boat after 24 hours. For example, the liquidus temperature exhibited by the glass compositions of this disclosure can be 1125°C, 1120°C, 1115°C, 1110°C, 1105°C, 1100°C, 1075°C, 1050°C, 1025°C, or even as low as 1000°C, as measured internally in a gradient boat after 24 hours.

[0127] In some embodiments, the glass compositions of this disclosure are configured to be radiation resistant, for example, as necessary for performance in space applications. In some embodiments, and without being bound by theory, the glass compositions of this disclosure may exhibit a transmittance loss of no more than 50% in the visible spectrum after exposure to radiation designed to simulate extraterrestrial environments. Specifically, these compositions exhibit limited or no change in transmittance after exposure to radiation associated with X-ray fluorescence (XRF) composition measurements using a wavelength dispersive X-ray fluorescence spectrometer (e.g., the Malvern Panaco Axios Advanced X-ray Spectrometer or its Axios Max Spectrometer with tubes operating at 3000 W power, 30 kV, and 100 mA). That is, these glass compositions experience minimal degradation (e.g., no yellowing, discoloration, etc.) after such exposure, as quantified by a transmittance loss of no more than 50%.

[0128] In the embodiments, the liquidus viscosity of the glass composition may be greater than or equal to 5 kP, greater than or equal to 50 kP, greater than or equal to 100 kP, or even greater than or equal to 115 kP. In the embodiments, the liquidus viscosity of the glass composition may be less than or equal to 133 kP, less than or equal to 100 kP, less than or equal to 75 kP, less than or equal to 50 kP, less than or equal to 20 kP, or even less than or equal to 10 kP.

[0129] In embodiments, the liquidus viscosity of the glass composition may be less than or equal to 780 kP, less than or equal to 700 kP, less than or equal to 600 kP, less than or equal to 500 kP, less than or equal to 400 kP, less than or equal to 300 kP, less than or equal to 200 kP, or even less than or equal to 100 kP. In embodiments, the liquidus viscosity of the glass composition may be greater than or equal to 31 kP and less than or equal to 780 kP, greater than or equal to 100 kP and less than or equal to 500 kP, greater than or equal to 150 kP and less than or equal to 350 kP, greater than or equal to 31 kP and less than or equal to 250 kP, or any and all subranges formed by any of these endpoints. These viscosity ranges allow the glass composition to be formed into sheets using a variety of different techniques, including but not limited to melt molding, slot drawing, float glass (e.g., float glass process), rolling, and other sheet forming processes known to those skilled in the art. However, it should be understood that other processes may be used to form other articles (i.e., other than sheets).

[0130] In the embodiments, the glass compositions described herein are ion-exchangeable to facilitate the strengthening of glass articles made from the glass compositions. In a typical ion-exchange process, smaller metal ions in the glass composition are replaced or "exchanged" by larger metal ions of the same valence state within a layer near the outer surface of the glass article made from the glass composition. The replacement of smaller ions with larger ions generates compressive stress within the layers of the glass article made from the glass composition. In the embodiments, the metal ions are monovalent metal ions (e.g., Li). + Na + K + (etc.), and ion exchange is achieved by immersing glass articles made of a glass composition in a bath containing at least one molten salt containing larger metal ions, which replace smaller metal ions in the glass articles. Alternatively, other monovalent ions (such as Ag) + 、Tl + Cu + (etc.) can be exchanged for monovalent ions. One or more ion exchange processes used to strengthen glass articles made of glass compositions may include, but are not limited to, immersion in a single or multiple baths of the same or different compositions, with washing and / or annealing steps between immersions.

[0131] A cooling scheme should be prudently defined to produce one or more of the following desired properties: the crystalline phase of the glass article, the ratio of one or more primary crystalline phases and / or one or more secondary crystalline phases to the glass, the crystalline phase combination of one or more primary crystalline phases and / or one or more secondary crystalline phases with the glass, and the grain size or grain size distribution among one or more primary crystalline phases and / or one or more secondary crystalline phases, which may in turn affect the final integrity, quality, color, and / or opacity of the resulting glass article. In embodiments, the crystalline phase of the glass article may include, but is not limited to, cerium calcite, cristobalite, mullite, and / or combinations thereof. The resulting glass may be provided as a sheet, which can then be reshaped into a uniformly thick bent or folded sheet by pressing, blow molding, bending, drooping, vacuum forming, or other methods. Reshaping can be performed prior to heat treatment, or the shaping step can also be used as a heat treatment step, wherein shaping and heat treatment are performed substantially simultaneously.

[0132] As previously described, the glass compositions of this disclosure are based on the soda-lime glass family, which provides UV blocking properties. Furthermore, the glass compositions of this disclosure exhibit optical and radiation resistance properties similar to those of historically obsolete UV-blocking glass compositions, and demonstrate superior optical and radiation resistance performance compared to current comparative glass compositions used in space applications. Indeed, as shown in Table 1 below, the two example glass compositions of this disclosure (Examples 1J and 1AE, detailed in the Examples section below) exhibit 50% transmittance cutoff wavelengths of 335 nm and 320 nm, respectively. This reflects performance superior to the 300 nm 50% transmittance cutoff wavelength of current comparative glass compositions used in space applications (i.e., Comparative Example 1A, detailed in the Examples section below), and comparable to the 50% transmittance cutoff wavelength of historically obsolete UV-blocking compositions (e.g., Comparative Examples 1B and 1C, detailed in the Examples section below).

[0133] Table 1 – Summary of optical and radiation resistance data for glass compositions

[0134]

[0135]

[0136] Now for reference Figure 2 The graph provides plots of transmittance (%) against UV (ultraviolet) spectra for comparative glass compositions (Comparative Examples 1A and 1B) and example glass compositions (Examples 1A, 1C, 1G, 1J, 1I), as measured at a thickness of 50 µm. Figure 2 It is evident that using specific amounts of cerium and titanium allows the glass compositions of this disclosure to completely or partially block UV light within a certain wavelength range. Titanium absorbs primarily at about 290-300 nm, while cerium exists in silicate glasses in two different valence states (Ce... 4+ and Ce 3+ The presence of these elements induces absorption in the UV region, exhibiting a broad peak centered at approximately 240 nm and an asymmetric narrow peak with maximum absorption near 300–320 nm. With smaller thicknesses and without theoretical constraints, a combination of two elements (Ti and Ce) is required to enhance the UV blocking effect and minimize the shoulders present in the transmittance profile of the glass composition in this space.

[0137] Example

[0138] The following examples illustrate certain non-limiting examples of glass compositions and articles of this disclosure.

[0139] Compare Examples 1A-1C

[0140] In this comparative example, the comparative glass compositions are summarized in Table 2 below. Comparative Example 1A is a current UV blocking composition used in space applications. Comparative Examples 1B and 1C are obsolete historical UV blocking compositions that cannot be manufactured economically on current glass-forming equipment. It is noteworthy, and evident from the preceding Table 1, that the glass compositions of this disclosure exhibit similar optical and radiation resistance properties to historical obsolete UV blocking glass compositions (Comparative Examples 1B and 1C), and better optical and radiation resistance performance than the current comparative glass composition (Comparative Example 1A) used in space applications. Although Comparative Example 1A does not employ CeO2, it does not exhibit significant radiation resistance suitable for space applications (see Table 1). As for Comparative Examples 1B and 1C, these compositions employ some CeO2, are radiation resistant, and have a reasonable 50% transmittance cutoff wavelength; nevertheless, the example glass compositions exhibit radiation resistance, have a better 50% transmittance cutoff wavelength, typically employ less CeO2, and have a higher TiO2 content.

[0141] Table 2 – Comparison of Glass Compositions

[0142]

[0143]

[0144] Example 1 (Example 1A-1R (without ZnO))

[0145] In these examples, glass compositions of this disclosure (designated as Examples 1A-1R, as listed in Table 3) without ZnO content have been melted according to the method of this disclosure. The batch materials were mixed in appropriate quantities (i.e., as illustrated in Table 3) and melted in a covered platinum crucible at 1625°C for 6 hours in a gas furnace, then poured into water. The glass was then combined with the residual glass remaining in the crucible. All the glass was then ball-milled into powder and remelted at 1650°C for 12 hours, then poured onto a steel plate as a cake. Selected properties associated with these glass compositions, including density, CTE, and viscosity, are presented in Table 3. Additionally, for some of these glass compositions, the 50% transmittance cutoff wavelength, measured at a thickness of 50 µm, is provided.

[0146] Table 3 - Example Glass Compositions

[0147]

[0148]

[0149] Continued Table 3 - Example Glass Compositions

[0150]

[0151]

[0152] Continued Table 3 - Example Glass Compositions

[0153]

[0154]

[0155] Example 2 (Example 1S-1AA (with ZnO))

[0156] In these examples, glass compositions of this disclosure with ZnO content (designated as Examples 1S-1AA, listed in Table 4 below) have been melted according to the method of this disclosure. The batch materials were mixed in appropriate quantities (i.e., as illustrated in Table 4) and melted in a covered platinum crucible at 1625°C for 6 hours in a gas furnace, then poured into water. The glass was then combined with the residual glass remaining in the crucible. All the glass was then ball-milled into powder and remelted at 1650°C for 12 hours, then poured onto a steel plate as a cake. Selected properties associated with these glass compositions, including density, CTE, and viscosity, are presented in Table 4. Additionally, for some of these glass compositions, the 50% transmittance cutoff wavelength, as measured at a thickness of 50 µm, is provided.

[0157] Table 4 - Example glass compositions containing ZnO

[0158]

[0159]

[0160] Continued Table 4 - Example glass compositions containing ZnO

[0161]

[0162]

[0163] Example 3 (Example 1AB-1AR)

[0164] In these examples, the glass compositions of this disclosure (designated as Examples 1AB-1AR, as listed in Table 5 below) have been melted according to the method of this disclosure. The batch materials were mixed in appropriate quantities (i.e., as illustrated in Table 5) and melted in a covered platinum crucible at 1625°C for 6 hours in a gas furnace, then poured into water. The glass was then combined with the residual glass remaining in the crucible. All the glass was then ball-milled into powder and remelted at 1650°C for 12 hours, then poured onto a steel plate as a cake. Selected properties associated with these glass compositions, including density, CTE, and viscosity, are presented in Table 5. Additionally, for some of these glass compositions, the 50% transmittance cutoff wavelength, as measured at a thickness of 50 µm, is provided.

[0165] Table 5 - Example Glass Compositions

[0166]

[0167]

[0168] Continued Table 5 - Example Glass Compositions

[0169]

[0170]

[0171] Continued Table 5 - Example glass compositions (CeO2-free)

[0172]

[0173]

[0174] Continued Table 5 - Example Glass Compositions

[0175]

[0176]

[0177] Summary of Examples 1-3

[0178] refer to Figure 3A The graph provides a plot of transmittance (%) against UV spectra for example glass compositions (Examples 1A, 1C, 1G, and 1H from Example 1 above). It is evident from the graph that these example glass compositions exhibit a good 50% transmittance cutoff point of at least 330 nm.

[0179] refer to Figure 3BThe graph provides a plot of transmittance (%) against UV spectra for example glass compositions (Examples 1Y, 1AC, 1M, 1N, and 1O from Examples 1-3 above). It is evident from the graph that most of these example glass compositions exhibit a good 50% transmittance cutoff of at least 325 nm (Example 1Y exhibits a 50% transmittance cutoff of approximately 295 nm).

[0180] refer to Figure 3C The graph provides a plot of transmittance (%) against UV spectra for example glass compositions (Examples 1Z, 1AD, 1P, 1Q, and 1R from Examples 1-3 above). It is evident from the graph that most of these example glass compositions exhibit a good 50% transmittance cutoff of at least 325 nm (Example 1Z exhibits a 50% transmittance cutoff of approximately 301 nm).

[0181] Example 4 - Etching

[0182] In this example, example glass compositions (Examples 1AA, 1Z, 1Y, 1R, 1Q, 1P, 1O, 1N, and 1M) were etched in a 3.7 M HF solution at ambient temperature (21°C) for approximately 20 minutes to approximately 330 minutes. The glass removal depth (µm) was measured at each of these durations. See also... Figure 4 The glass removal depth (µm) for these examples was plotted as a function of etching duration (minutes). Using this data, the etching rate (µm / min) for each of these glass compositions was calculated. As is evident from Table 6 below, the etching rates for these glass compositions range from approximately 0.58 µm / min to 1.10 µm / min.

[0183] Table 6 – Etching rates of example glass compositions

[0184]

[0185]

[0186] Example 5 - Irradiation

[0187] In this example, the exemplary glass composition of this disclosure has been irradiated to qualitatively simulate the radiation that solar panels installed in a satellite are expected to receive during spaceflight and orbit. Specifically, the example glass composition was irradiated using wavelength dispersive X-ray fluorescence spectrometry, with measurements taken from standard XRF spectroscopy. Additionally, some samples were set aside as controls and were not irradiated.

[0188] Figure 5The results of the qualitative test for this example are shown in the figure. Specifically, Figure 5 The images include photographs of example glass compositions (Examples 1Y, 1AC, and 1M) that were neither irradiated nor irradiated by X-ray fluorescence (XRF) spectroscopy. Additionally, some of the glass compositions (Examples 1Z, 1AD, and 1P) were irradiated only by XRF. It is evident from the figures that irradiation exposure does tend to cause the samples to darken to some extent. However, for the examples with the highest TiO2 and CeO2 contents, the degree of darkening is less significant.

[0189] The various features described in the specification can be combined in any and all combinations, such as those listed in the following examples.

[0190] Example 1. A glass composition is provided, comprising:

[0191] Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2;

[0192] Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3;

[0193] MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%;

[0194] Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO;

[0195] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO;

[0196] Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O;

[0197] Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O;

[0198] Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and

[0199] CeO2, greater than or equal to 0 mol% to less than or equal to 1.5 mol%.

[0200] Example 2. A glass composition according to Example 1 is provided, further comprising:

[0201] Greater than or equal to 66.7 mol% to less than or equal to 78.0 mol% SiO2;

[0202] Greater than or equal to 4.9 mol% to less than or equal to 12.6 mol% Al2O3;

[0203] MgO concentration greater than or equal to 2.3 mol% to less than or equal to 3.2 mol%;

[0204] Greater than or equal to 1.2 mol% to less than or equal to 3.4 mol% CaO;

[0205] Greater than or equal to 0 mol% to less than or equal to 1.0 mol% ZnO;

[0206] Greater than or equal to 5.1 mol% to less than or equal to 15.0 mol% Na2O;

[0207] Greater than or equal to 0 mol% to less than or equal to 4.6 mol% K₂O; and

[0208] Greater than or equal to 0.1 mol% to less than or equal to 0.18 mol% SnO2.

[0209] Example 3. A glass composition according to Example 1 is provided, wherein the glass composition is substantially free of B2O3.

[0210] Example 4. A glass composition according to Example 1 is provided, further comprising:

[0211] Greater than 0.1 mol% to less than or equal to 1.5 mol% CeO2.

[0212] Example 5. A glass composition according to Example 4 is provided, wherein, in X-ray fluorescence composition measurements using a wavelength dispersive X-ray fluorescence (XRF) spectrometer, the glass composition exhibits a transmittance loss of no more than 50% in the visible spectrum after irradiation.

[0213] Example 6. A glass composition according to Example 1 is provided, wherein the density of the glass composition is 2.5 g / cc or less.

[0214] Example 7. A glass composition according to Example 1 is provided, wherein the liquidus temperature of the glass composition is less than 1115°C, as measured inside a gradient boat after 24 hours.

[0215] Example 8. A glass composition is provided, comprising:

[0216] Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2;

[0217] Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3;

[0218] MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%;

[0219] Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO;

[0220] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO;

[0221] Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O;

[0222] Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O;

[0223] Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and

[0224] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% CeO2,

[0225] The glass composition, with a thickness of 50 µm, has a transmittance of 50% in the ultraviolet wavelength (UV) range of 320 nm to 350 nm.

[0226] Example 9. A glass composition according to Example 8 is provided, further comprising:

[0227] Greater than or equal to 66.7 mol% to less than or equal to 78.0 mol% SiO2;

[0228] Greater than or equal to 4.9 mol% to less than or equal to 12.6 mol% Al2O3;

[0229] MgO concentration greater than or equal to 2.3 mol% to less than or equal to 3.2 mol%;

[0230] Greater than or equal to 1.2 mol% to less than or equal to 3.4 mol% CaO;

[0231] Greater than or equal to 0 mol% to less than or equal to 1.0 mol% ZnO;

[0232] Greater than or equal to 5.1 mol% to less than or equal to 15.0 mol% Na2O;

[0233] Greater than or equal to 0 mol% to less than or equal to 4.6 mol% K₂O; and

[0234] Greater than or equal to 0.1 mol% to less than or equal to 0.18 mol% SnO2.

[0235] Example 10. A glass composition according to Example 8 is provided, wherein the glass composition is substantially free of B2O3.

[0236] Example 11. A glass composition according to Example 8 is provided, further comprising:

[0237] Greater than 0.1 mol% to less than or equal to 1.5 mol% CeO2.

[0238] Example 12. A glass composition according to Example 11 is provided, wherein, in X-ray fluorescence composition measurements using a wavelength dispersive X-ray fluorescence (XRF) spectrometer, the glass composition exhibits a transmittance loss of no more than 50% in the visible spectrum after irradiation.

[0239] Example 13. A glass composition according to Example 8 is provided, wherein the density of the glass composition is 2.5 g / cc or less.

[0240] Example 14. A glass composition according to Example 8 is provided, wherein the liquidus temperature of the glass composition is less than 1115°C, as measured inside a gradient boat after 24 hours.

[0241] Example 15. A glass composition according to Example 8 is provided, wherein the glass composition has a transmittance percentage of 50% in the ultraviolet wavelength (UV) range of 340 nm to 350 nm at a thickness of 50 µm.

[0242] Example 16. A glass composition is provided, comprising:

[0243] Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2;

[0244] Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3;

[0245] MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%;

[0246] Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO;

[0247] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO;

[0248] Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O;

[0249] Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O;

[0250] Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and

[0251] Greater than or equal to 0 mol% to less than or equal to 1.5 mol% CeO2,

[0252] The glass composition, at a thickness of 50 µm, has a transmittance of 50% in the ultraviolet (UV) wavelength range of 320 nm to 350 nm.

[0253] The coefficient of thermal expansion (CTE) of the glass composition, measured at temperatures between 100°C and 300°C, is 69 × 10⁻⁶. -7 / ℃ to 75 × 10 -7 / ℃.

[0254] Example 17. A glass composition according to Example 16 is provided, further comprising:

[0255] Greater than or equal to 66.7 mol% to less than or equal to 78.0 mol% SiO2;

[0256] Greater than or equal to 4.9 mol% to less than or equal to 12.6 mol% Al2O3;

[0257] MgO concentration greater than or equal to 2.3 mol% to less than or equal to 3.2 mol%;

[0258] Greater than or equal to 1.2 mol% to less than or equal to 3.4 mol% CaO;

[0259] Greater than or equal to 0 mol% to less than or equal to 1.0 mol% ZnO;

[0260] Greater than or equal to 5.1 mol% to less than or equal to 15.0 mol% Na2O;

[0261] Greater than or equal to 0 mol% to less than or equal to 4.6 mol% K₂O; and

[0262] Greater than or equal to 0.1 mol% to less than or equal to 0.18 mol% SnO2.

[0263] Example 18. A glass composition according to Example 16 is provided, wherein the glass composition is substantially free of B2O3.

[0264] Example 19. A glass composition according to Example 16 is provided, further comprising:

[0265] Greater than 0.1 mol% to less than or equal to 1.5 mol% CeO2.

[0266] Example 20. A glass composition according to Example 19 is provided, wherein, in X-ray fluorescence composition measurements using a wavelength dispersive X-ray fluorescence (XRF) spectrometer, the glass composition exhibits a transmittance loss of no more than 50% in the visible spectrum after irradiation.

[0267] Example 21. A glass composition according to Example 16 is provided, wherein the density of the glass composition is 2.5 g / cc or less.

[0268] Example 22. A glass composition according to Example 16 is provided, wherein the liquidus temperature of the glass composition is less than 1115°C, as measured inside a gradient boat after 24 hours.

[0269] Example 23. A glass composition according to Example 16 is provided, wherein the coefficient of thermal expansion (CTE) of the glass composition, measured at 100°C to 300°C, is 72 × 10⁻⁶. -7 / ℃ to 74 × 10 -7 / ℃.

Claims

1. A glass composition comprising: Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2; Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3; MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%; Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO; Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO; Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O; Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O; Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and CeO2, greater than or equal to 0 mol% to less than or equal to 1.5 mol%.

2. The glass composition according to claim 1, further comprising: Greater than or equal to 66.7 mol% to less than or equal to 78.0 mol% SiO2; Greater than or equal to 4.9 mol% to less than or equal to 12.6 mol% Al2O3; MgO concentration greater than or equal to 2.3 mol% to less than or equal to 3.2 mol%; Greater than or equal to 1.2 mol% to less than or equal to 3.4 mol% CaO; Greater than or equal to 0 mol% to less than or equal to 1.0 mol% ZnO; Greater than or equal to 5.1 mol% to less than or equal to 15.0 mol% Na2O; Greater than or equal to 0 mol% to less than or equal to 4.6 mol% K₂O; and Greater than or equal to 0.1 mol% to less than or equal to 0.18 mol% SnO2.

3. The glass composition according to any one of claims 1 or 2, wherein the glass composition is substantially free of B2O3.

4. The glass composition according to any one of claims 1 to 3, further comprising: Greater than 0.1 mol% to less than or equal to 1.5 mol% CeO2.

5. The glass composition according to claim 4, wherein, in the X-ray fluorescence composition measurement using a wavelength dispersive X-ray fluorescence (XRF) spectrometer, the glass composition exhibits a transmittance loss of no more than 50% in the visible spectrum after irradiation.

6. The glass composition according to any one of claims 1 to 5, wherein the density of the glass composition is 2.5 g / cc or less.

7. The glass composition according to any one of claims 1 to 6, wherein the liquidus temperature of the glass composition is less than 1115°C, as measured inside a gradient boat after 24 hours.

8. A glass composition comprising: Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2; Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3; MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%; Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO; Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO; Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O; Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O; Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and Greater than or equal to 0 mol% to less than or equal to 1.5 mol% CeO2, The glass composition, with a thickness of 50 µm, has a transmittance of 50% in the ultraviolet wavelength (UV) range of 320 nm to 350 nm.

9. The glass composition according to claim 8, further comprising: Greater than or equal to 66.7 mol% to less than or equal to 78.0 mol% SiO2; Greater than or equal to 4.9 mol% to less than or equal to 12.6 mol% Al2O3; MgO concentration greater than or equal to 2.3 mol% to less than or equal to 3.2 mol%; Greater than or equal to 1.2 mol% to less than or equal to 3.4 mol% CaO; Greater than or equal to 0 mol% to less than or equal to 1.0 mol% ZnO; Greater than or equal to 5.1 mol% to less than or equal to 15.0 mol% Na2O; Greater than or equal to 0 mol% to less than or equal to 4.6 mol% K₂O; and Greater than or equal to 0.1 mol% to less than or equal to 0.18 mol% SnO2.

10. The glass composition according to claim 8 or claim 9, wherein the glass composition is substantially free of B2O3.

11. The glass composition according to any one of claims 8 to 10, further comprising: Greater than 0.1 mol% to less than or equal to 1.5 mol% CeO2.

12. The glass composition according to claim 11, wherein, in the X-ray fluorescence composition measurement using a wavelength dispersive X-ray fluorescence (XRF) spectrometer, the glass composition exhibits a transmittance loss of no more than 50% in the visible spectrum after irradiation.

13. The glass composition according to any one of claims 8 to 12, wherein the density of the glass composition is 2.5 g / cc or less.

14. The glass composition according to any one of claims 8 to 13, wherein the liquidus temperature of the glass composition is less than 1115°C, as measured inside a gradient boat after 24 hours.

15. The glass composition according to any one of claims 8 to 14, wherein the glass composition has a transmittance percentage of 50% at ultraviolet wavelengths (UV) in the range of 340 nm to 350 nm at a thickness of 50 µm.

16. A glass composition comprising: Greater than or equal to 65 mol% to less than or equal to 79 mol% SiO2; Greater than or equal to 4 mol% to less than or equal to 13.5 mol% Al2O3; MgO concentration greater than or equal to 1.5 mol% to less than or equal to 4.0 mol%; Greater than or equal to 1 mol% to less than or equal to 4 mol% CaO; Greater than or equal to 0 mol% to less than or equal to 1.5 mol% ZnO; Greater than or equal to 4 mol% to less than or equal to 16 mol% Na2O; Greater than or equal to 0 mol% to less than or equal to 5.5 mol% K2O; Greater than or equal to 0.4 mol% to less than or equal to 2.5 mol% TiO2; and Greater than or equal to 0 mol% to less than or equal to 1.5 mol% CeO2, The glass composition, at a thickness of 50 µm, has a transmittance of 50% in the ultraviolet (UV) wavelength range of 320 nm to 350 nm. The coefficient of thermal expansion (CTE) of the glass composition, measured at temperatures between 100°C and 300°C, is 69 × 10⁻⁶. -7 / ℃ to 75× 10 -7 / ℃.

17. The glass composition according to claim 16, further comprising: Greater than or equal to 66.7 mol% to less than or equal to 78.0 mol% SiO2; Greater than or equal to 4.9 mol% to less than or equal to 12.6 mol% Al2O3; MgO concentration greater than or equal to 2.3 mol% to less than or equal to 3.2 mol%; Greater than or equal to 1.2 mol% to less than or equal to 3.4 mol% CaO; Greater than or equal to 0 mol% to less than or equal to 1.0 mol% ZnO; Greater than or equal to 5.1 mol% to less than or equal to 15.0 mol% Na2O; Greater than or equal to 0 mol% to less than or equal to 4.6 mol% K₂O; and Greater than or equal to 0.1 mol% to less than or equal to 0.18 mol% SnO2.

18. The glass composition according to claim 16 or claim 17, wherein the glass composition is substantially free of B2O3.

19. The glass composition according to any one of claims 16 to 18, further comprising: Greater than 0.1 mol% to less than or equal to 1.5 mol% CeO2.

20. The glass composition of claim 19, wherein, in the X-ray fluorescence composition measurement using a wavelength dispersive X-ray fluorescence (XRF) spectrometer, the glass composition exhibits a transmittance loss of no more than 50% in the visible spectrum after irradiation.

21. The glass composition according to any one of claims 16 to 20, wherein the density of the glass composition is 2.5 g / cc or less.

22. The glass composition according to any one of claims 16 to 21, wherein the liquidus temperature of the glass composition is less than 1115°C, as measured inside a gradient boat after 24 hours.

23. The glass composition according to any one of claims 16 to 22, wherein the coefficient of thermal expansion (CTE) of the glass composition, measured at 100°C to 300°C, is 72 × 10⁻⁶. -7 / ℃ to 74 × 10 -7 / ℃.

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