An environmentally friendly low-refractive-index corrosion-resistant glass and its preparation method

Abstract

This invention relates to the field of optical fiber imaging and the preparation of its glass materials, and particularly to an environmentally friendly, low-refractive-index, corrosion-resistant glass and its preparation method. Its composition, by molar percentage, comprises the following components: 68-82% SiO2, 3.5-8% B2O3, 0.1-0.3% CeO2, 8-14% alkali metal oxides, 3-9% Al2O3, 1-5% alkaline earth metal oxides, and 0.1-1.5% CaF2, 0.1-0.5% ZrO2, and 0.1-0.5% Y2O3. The total content of SiO2, Al2O3, and B2O3 in this composition is 84-91%. The glass material provided by this invention has a low refractive index and suitable thermal expansion coefficient and softening temperature properties, and can be used as a skin glass material in the fabrication of optical glass fibers and fiber optic panels.

Description

Technical Field

[0001] This invention relates to the field of optical fiber imaging and the preparation of glass materials, and particularly to an environmentally friendly, low-refractive-index, corrosion-resistant glass and its preparation method. Background Technology

[0002] Any discussion of prior art throughout the specification should not be construed as an admission that such prior art is well-known or constitutes part of common general knowledge in the art.

[0003] In modern minimally invasive medical technology, fiber optic cones serve as the "visual nerves" of endoscopic diagnostic systems, and their performance directly determines diagnostic accuracy and treatment safety. While traditional fiber optic cone glass can meet basic optical requirements, it has significant drawbacks in medical settings: its heavy metal content, such as lead, is subject to environmental regulations; frequent sterilization leads to material corrosion, affecting light transmission stability; and it generates hazardous waste upon disposal. With increasingly stringent environmental regulations restricting lead in medical glass and the ever-increasing precision requirements of clinical minimally invasive procedures, the development of environmentally friendly, corrosion-resistant, low-refractive-index glass has become crucial for the advancement of medical fiber optic technology.

[0004] The working environment of medical fiber optic cones places extremely high demands on the glass material used for the fiber optic coating. In applications such as gastrointestinal endoscopy and laparoscopy, the fiber optic cone must withstand repeated, intensive sterilization and the corrosive effects of the acidic environment inside the stomach. Traditional silicate glass is prone to surface degradation during sterilization and is subject to gastric acid corrosion during gastroscopy, leading to increased light transmission loss and even image distortion. Furthermore, traditional low-refractive-index glass often introduces heavy metal oxides, which, if released due to material wear, could pose safety risks. Relevant standards strictly limit heavy metal elements in medical devices, posing a compliance crisis for fiber optic cones that rely on lead-based glass. In addition, traditional low-refractive-index glass struggles to balance optical performance with environmental requirements, and existing lead-free glass solutions also suffer from issues such as excessively high refractive indices or insufficient chemical stability.

[0005] Given the specific needs of medical settings, environmentally friendly coring glasses must possess excellent optical performance, environmental adaptability, and biocompatibility. In terms of optical parameter design, a stable low refractive index gradient distribution is required to meet the demands of high-definition imaging. Regarding corrosion resistance, the material must withstand multiple sterilization processes without significant corrosion and repeatedly resist the erosion of stomach acid within the human body without noticeable corrosion. Environmental characteristics must be maintained throughout the entire material lifecycle, including production, use, and disposal. In terms of biocompatibility, the new glass must pass relevant safety tests to ensure safe clinical applications. Therefore, developing environmentally friendly, low-refractive-index, corrosion-resistant coring glasses is a crucial step in meeting current environmental requirements and promoting the sustainable development of fiber optic cone technology. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an environmentally friendly low-refractive-index corrosion-resistant glass and its preparation method. The glass material provided by this invention has a refractive index ≤1.48 and suitable thermal expansion coefficient and softening temperature properties, making it suitable as a skin glass material for the fabrication of optical glass fibers and fiber optic panels. Furthermore, the glass material of this invention ensures that its viscosity matches that of the core glass material, especially core glass materials with a refractive index ≥1.8, which is beneficial for the fiber drawing process and provides good processability and adaptability. The prepared glass does not contain any environmentally harmful heavy metal oxides (such as As₂O₃, Bi₂O₃, PbO, etc.); and it possesses high chemical stability, which improves the glass's corrosion resistance, extends its service life, and reduces resource waste caused by frequent product replacements. In optical devices such as optical lenses and optical fibers, the high chemical stability of the low-refractive-index skin glass ensures that it remains unaffected by environmental factors during long-term use, maintaining good optical performance. For example, in outdoor optical monitoring equipment, facing complex natural environments, the low-refractive-index skin glass can resist erosion from rain, wind, and sand, ensuring the normal operation of the equipment and imaging quality.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides an environmentally friendly low-refractive-index corrosion-resistant glass, the composition of which, by molar percentage, comprises the following components: 68-82% SiO2, 3.5-8% B2O3, 0.1-0.3% CeO2, 8-14% alkali metal oxides, 3-9% Al2O3, 1-5% alkaline earth metal oxides, and 0.1-1.5% CaF2, 0.1-0.5% ZrO2, and 0.1-0.5% Y2O3. The total content of SiO2, Al2O3, and B2O3 in the composition is 84-91%, the alkali metal oxides are selected from Na2O and K2O, and the alkaline earth metal oxides are selected from at least one of CaO and MgO.

[0009] Silica has a low refractive index in glass. Appropriately increasing the silica content can lower the glass's refractive index, but this also increases the glass's viscosity (softening point), affecting its compatibility with the core glass. Similarly, fluorite also has a low refractive index in glass. Introducing and increasing the fluorite content can lower the glass's refractive index, but this also increases the coefficient of thermal expansion, further affecting its compatibility with the core glass. This is a major problem currently faced in the preparation of low-refractive-index glasses. Therefore, solving these problems and / or improving compatibility with the core glass is the key technical challenge that this invention aims to address. The main basic components of this invention are silica, which forms the glass network structure; boron oxide (B₂O₃) and aluminum oxide (Al₂O₃), which are network intermediates; and alkali metals (K₂O, Na₂O) and alkaline earth metals (at least one of CaO and MgO). CeO₂ is selected based on this, and yttrium oxide and zirconium oxide are added to increase its erosiveness and mechanical strength.

[0010] In embodiments of the present invention, SiO2 is the basic framework of the glass network structure and a major component of environmentally friendly, low-refractive-index, corrosion-resistant glass. In the glass described in this invention, the molar content of SiO2 is 68-82% to maintain the glass's tensile strength, chemical stability, viscosity, and coefficient of thermal expansion. In some embodiments of the present invention, the molar content of SiO2 is 68-82%, 68-80%, 68-78%, 68-76%, 68-74%, 68-72%, 68-70%, 70-72%, etc. Preferably, the molar content of SiO2 is 68-75.1%, 68-70.7%, 68-69.8%, 70.7-72.7%, 68-72.7%, or 70.7-82%.

[0011] B₂O₃, as a glass-forming oxide, can form glass on its own. In silicate glasses, B can partially replace Si to form a network structure. Furthermore, B₂O₃ acts as a flux in glass, reducing its high-temperature viscosity, saving costs and facilitating production. However, as the B₂O₃ content increases, the devitrification range of the glass increases, and B₂O₃ is volatile and can pollute the environment; therefore, its usage should be strictly controlled during production. Therefore, the glass material provided by this invention has a B₂O₃ molar content of 3.5-8%. In some embodiments of this invention, the B₂O₃ molar content is 3.5-4.5%, 3.5-7.9%, 3.5-7%, 4-5.2%, 4-8%, 5.2-7.2%, 5.2-7.9%, 5.2-7%, 7-8%, etc. Preferably, the molar content of B2O3 is 4.1~4.7%, 4.5~7.9%, 7.2~8%, 5.2~6.8%, 6.9~7.2%, or 7.2~7.8%.

[0012] Al₂O₃, as a network intermediate in forming the glass structure, affects the glass's coefficient of thermal expansion and its chemical and thermal stability. Al₂O₃ can increase the glass's machinability, but excessive amounts will reduce its material properties. In the glass described in this invention, the molar content of Al₂O₃ is 3-9%. In some embodiments of this invention, the molar content of Al₂O₃ is 3-3.9%, 3-4.9%, 3.9-7%, 3.1-5.1%, 3.1-5.9%, 4.9-7%, 4.9-5.1%, and 5.1-7%, etc. Preferably, the molar content of Al₂O₃ is 3.1-4.1% or 4.1-7%.

[0013] In this invention, SiO2, B2O3 and Al2O3 serve as network formers and intermediates of the glass structure. To provide high chemical stability, the total molar content of SiO2, Al2O3 and B2O3 is 84-91%. In some embodiments of this invention, the total molar content of SiO2, Al2O3 and B2O3 is 84-86%, 86-88%, or 88-91%, etc.

[0014] CeO2 has a variable valence state in this invention (Ce 3+ and Ce 4+ At high temperatures, Ce 4+ It can release oxygen, which can react with low-valence elements in the glass melt, oxidizing them to high-valence elements and thus being released as gas, achieving the effect of clarifying the glass. Simultaneously, the oxygen produced by the decomposition of cerium oxide can reduce the partial pressure of other gases in the glass melt, promoting the escape of gases from bubbles, reducing bubble residue in the glass, and improving the transparency and optical uniformity of the glass. However, excessive introduction of CeO2 will reduce the transmittance of the glass, especially in the near-ultraviolet range, and the addition of CeO2 will increase the refractive index of the glass. Therefore, in the glass described in this invention, the molar content of CeO2 is controlled at 0.1~0.3%. In some embodiments of this invention, the molar content of CeO2 is 0.1~0.2%, 0.2~0.3%, etc.

[0015] Na₂O and K₂O are network oxides in glass. Alkali metal ions readily move and diffuse within the glass, reducing the viscosity of the glass during high-temperature melting, making it easier to melt. They are excellent fluxes, but also increase the coefficient of thermal expansion and decrease the glass's chemical stability and mechanical strength. In the glass described in this invention, the molar content of the alkali metal oxides is 8-14%, preferably 8-10%, 10-12%, or 12-14%. In some embodiments of this invention, the molar content of Na₂O is 2-5%, and the molar content of K₂O is 6-12%. The molar content of Na₂O can be selected from the following ranges: 2-5%, 2-4%, 2-3%, 3-5%, 4-5%, etc., and the molar content of K₂O can be selected from the following ranges: 6-8.3%, 6-6.9%, 6.9-9%, 6-9%, 6.3-9%, 7-9%, 8-9%, 9-12%, etc.

[0016] CaF2 possesses unique dispersion properties and is commonly used as an important material for correcting chromatic aberration in optical systems. Furthermore, CaF2 has a low refractive index; adding an appropriate amount of CaF2 can reduce the glass's refractive index. However, excessive addition can increase the glass's coefficient of thermal expansion, reducing its compatibility with the core material. In the glass described in this invention, the molar content of CaF2 is 0.1% to 1.5%. In some embodiments of this invention, the molar content of CaF2 is 0.1% to 1.5%, 0.1% to 1.2%, 0.1% to 1.0%, 0.1% to 0.8%, 0.2% to 0.3%, 0.2% to 0.5%, 0.2% to 0.8%, etc. Preferably, the molar content of CaF2 is 0.1% to 0.2%, 0.1% to 0.3%, 0.9% to 1.5%, 0.2% to 1.5%, or 0.3% to 1.5%.

[0017] The simultaneous use of ZrO2 and Y2O3 has a synergistic effect, which can effectively improve its corrosion resistance and mechanical strength. 3+With a high electric field strength, it can improve the density and strength of the glass network, fundamentally enhancing the chemical stability of the glass. Although yttrium oxide itself does not have an extremely high refractive index, its content needs to be precisely controlled and is not high, thus exerting its reinforcing effect without affecting its refractive index. In the glass described in this invention, the molar content of Y₂O₃ is 0.1~0.5%. In some embodiments of this invention, the molar content of Y₂O₃ can be selected from the following ranges: 0.1~0.4%, 0.1~0.3%, 0.1~0.2%, 0.2~0.3%, 0.2~0.4%, 0.2~0.5%, etc. Zirconia itself has excellent corrosion resistance; when incorporated into the glass network, it can significantly improve the glass's resistance to erosion. Similarly, the amount of zirconium oxide added is strictly controlled to improve corrosion resistance without affecting its refractive index. In the glass described in this invention, the molar content of ZrO₂ is 0.1~0.5%. In some embodiments of the present invention, the molar content of ZrO2 may be selected from the following ranges: 0.1~0.4%, 0.1~0.3%, 0.1~0.2%, 0.2~0.3%, 0.2~0.4%, 0.2~0.5%, etc.

[0018] In this invention, the addition of at least one alkaline earth metal oxide selected from CaO and MgO will greatly reduce the phase separation tendency of the glass. Therefore, the glass material of this invention needs to contain at least one alkaline earth metal oxide selected from CaO and MgO, and its molar content is 1 to 5%.

[0019] For example, in some embodiments of the present invention, the alkaline earth metal oxide contains at least MgO, and its molar content can be selected from the following content range: 0~1.5%; more preferably, the molar content of MgO is 0~0.5% or 0.1~0.5% or 0.1~0.3% or 0.2~0.5% or 0.5~1.5%.

[0020] For example, in some embodiments of the present invention, the alkaline earth metal oxide contains at least CaO, and its molar content is any content of 0 to 1.6%, preferably 1 to 1.6%.

[0021] As a preferred example, in the above embodiments of the present invention, the alkaline earth metal oxide may be MgO, or a combination of CaO and MgO. In some embodiments, the molar content of the alkaline earth metal oxide is 1.3~2%, 1.5~2%, 1.3~1.9%, or 2~5%.

[0022] The various specific technical features described in the above embodiments of the present invention can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0023] Unless otherwise specified, the numerical ranges described in this invention include all values ​​within this range, and also include any range of values ​​formed by any two values ​​within this range. For example, 0.1% to 0.3% CeO2, this numerical range includes all values ​​between 0.1% and 0.3%, and also includes any range of values ​​formed by any two values ​​within this range (e.g., 0.11% and 0.25%) (0.11%-0.25%). Different values ​​of the same indicator appearing in all embodiments of this invention can be arbitrarily combined to form a range value.

[0024] In some embodiments of the present invention, the glass material is a low-refractive-index environmentally friendly glass material with a refractive index ≤1.48. The low refractive index results in a larger light reception angle θ, allowing more light to enter the optical fiber, thus exhibiting good refractive properties. In some embodiments, the refractive index of the glass material of the present invention is ≤1.47.

[0025] In some embodiments of the present invention, the glass material has suitable glass transition temperature Tg, and / or expansion softening temperature Tf, and / or softening point temperature Ts, and / or coefficient of thermal expansion. More suitable parameters are Tg ≤ 580℃, Tf ≤ 670℃, Ts ≤ 775℃, and a coefficient of thermal expansion of (80~87)×10⁻⁶ at 20℃~300℃. -7 / ℃.

[0026] In another aspect, the present invention provides a method for preparing the environmentally friendly low-refractive-index corrosion-resistant glass described in the first aspect, comprising the following steps: mixing raw materials in proportion, melting the mixed raw materials at high temperature, stirring to assist in clarification and homogenization, drawing and forming, and annealing.

[0027] In some embodiments of the present invention, the high-temperature melting temperature is 1350~1550℃, the drawing temperature is 1050~1350℃, and the annealing temperature is 500~600℃. Based on the composition of the environmentally friendly low-refractive-index corrosion-resistant glass described in the first aspect of the present invention, the glass material prepared within this temperature range possesses stable properties, including but not limited to good refractive properties, good heat resistance, good processability, and good chemical stability. Of course, it is understood that within this temperature range, higher temperatures can shorten the preparation process compared to lower temperatures. If it is necessary to minimize time costs, those skilled in the art can select a relatively higher temperature within the temperature range disclosed in the present invention.

[0028] In some embodiments of the present invention, the raw materials include: quartz sand, boric acid, cerium oxide, sodium salt, potassium salt, aluminum source, fluorite, barium salt, calcium carbonate, magnesium carbonate, yttrium oxide, and zirconium oxide; wherein the sodium salt is sodium carbonate or sodium nitrate, the potassium salt is potassium carbonate or potassium nitrate, the aluminum source is aluminum hydroxide or aluminum oxide, and the barium salt is barium nitrate or barium carbonate.

[0029] Thirdly, the present invention provides the application of the environmentally friendly low-refractive-index corrosion-resistant glass described in the first aspect of the present invention in the skin glass for optical cones or optical glass fibers.

[0030] Compared to existing technologies, the advantages of this invention include: The glass material provided by this invention possesses high chemical stability, ensuring its long-term use is unaffected by environmental factors and resists erosion from rain, wind, and sand, maintaining excellent optical performance. It exhibits a low refractive index (all refractive indices not exceeding 1.48); while maintaining a low refractive index, it also possesses suitable thermal expansion coefficients and softening point temperatures. These excellent characteristics make it suitable for use as a skin glass material and it matches well with core glass materials. Its good processability and adaptability, when used as a skin glass material in conjunction with core glass materials, especially with high-refractive-index core glass materials, not only facilitates the fiber drawing process but also increases the numerical aperture of the fiber optic cone, significantly improving its performance. Simultaneously, it effectively reduces production costs. Furthermore, this invention does not contain environmentally harmful heavy metal oxides, making it an environmentally friendly low-refractive-index glass. Of course, any product implementing this invention does not necessarily need to achieve all the advantages described above simultaneously. However, the invention is optimal in that it can achieve all of the above advantages at the same time. For example, the environmentally friendly glass material provided by this invention has a low refractive index (≤1.48), does not show discoloration or peeling after being etched with acetic acid solution with pH ≤2.9±0.2 for more than 5 hours, and has glass transition temperatures Tg ≤580℃, Tf ≤670℃, and Ts ≤775℃. It has good corrosion resistance and can be used as a cladding glass. It can be matched with core glass materials, and its coefficient of thermal expansion in the range of 20℃ to 300℃ is (80~87)×10. -7 At / ℃, it has good thermal processing properties, which is beneficial for the molding and fabrication of large-size devices. Its overall performance is superior to similar materials at home and abroad. Attached Figure Description

[0031] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings, wherein: Figure 1This is a comparison chart of the visible light transmittance of the glass prepared in Example 1 of the present invention before and after acid etching.

[0032] Figure 2 This is a schematic diagram of the environmentally friendly, low-refractive-index, corrosion-resistant glass material prepared in Example 1 of the present invention. Detailed Implementation

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods or product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0035] In a first aspect, the present invention provides an environmentally friendly, low-refractive-index, corrosion-resistant glass material that can be used as a cladding glass. Its composition, by molar percentage, comprises the following components: 68-82% SiO2, 3.5-8% B2O3, 0.1-0.3% CeO2, 8-14% alkali metal oxides, 3-9% Al2O3, 1-5% alkaline earth metal oxides, 0.1-1.5% CaF2, 0.1-0.5% ZrO2, and 0.1-0.5% Y2O3. The total content of SiO2, Al2O3, and B2O3 in the composition is 84-91%. The alkali metal oxides are selected from Na2O and K2O, and the alkaline earth metal oxides are selected from at least one of CaO and MgO. The glass material described in this invention has suitable thermal expansion coefficient and softening temperature performance, good processability and process adaptability, and can be used as a glass material for the production of optical glass fibers and fiber optic cones. The prepared fiber optic cones also have good corrosion resistance, which can fundamentally meet the requirements of extreme environment applications.

[0036] Specifically, when the environmentally friendly low-refractive-index, high-chemical-stability glass material of the present invention is composed of the above-mentioned components, in some embodiments of the present invention, the refractive index of the glass is ≤1.48; in some embodiments of the present invention, the glass transition temperature Tg of the glass is ≤580℃; in some embodiments of the present invention, the expansion softening temperature Tf of the glass is ≤670℃; in some embodiments of the present invention, the softening point temperature Ts of the glass is ≤775℃, matching the core glass material; in some embodiments of the present invention, the coefficient of thermal expansion of the glass under temperature conditions of 20℃~300℃ is (80~87)×10⁻¹⁰. -7 / ℃; In some embodiments of the present invention, the glass does not exhibit discoloration or peeling after being etched with acetic acid solution with pH ≤ 2.9 ± 0.2 for more than 5 hours; and in some embodiments of the present invention, the glass material of the present invention simultaneously possesses the above-mentioned excellent properties, namely, a refractive index ≤ 1.48, a glass transition temperature Tg ≤ 580℃, an expansion softening temperature Tf ≤ 670℃, a softening point temperature Ts ≤ 775℃, and a coefficient of thermal expansion of (80~87) × 10. -7 It exhibits superior overall performance and shows no discoloration or peeling after being etched for more than 5 hours at / ℃ and with acetic acid solution of pH≤2.9±0.2. It is particularly suitable for the preparation of corrosion-resistant optical components or optical instruments.

[0037] Furthermore, the low-refractive-index corrosion-resistant glass material of this invention can be prepared by the following method: raw materials are mixed in a specified ratio, the mixture is melted at a high temperature of 1350-1550℃, clarified with auxiliary stirring, mechanically drawn at 1050-1350℃, and annealed at 500-600℃ to obtain the environmentally friendly low-refractive-index corrosion-resistant glass material. This method possesses process stability, and the glass material prepared within this temperature range exhibits stable properties, including but not limited to good refractive properties, good heat resistance, good processability, and good corrosion resistance. Of course, it is understood that within this temperature range, higher temperatures can shorten the preparation process compared to lower temperatures. If it is necessary to minimize time costs, those skilled in the art can select a relatively higher temperature within the temperature range disclosed in this invention.

[0038] Furthermore, in the preparation method of a low refractive index radiation-resistant glass material provided by the present invention, the raw materials include: quartz sand, boric acid or boric acid, cerium oxide, sodium carbonate or sodium nitrate, potassium carbonate or potassium nitrate, aluminum hydroxide or aluminum oxide, fluorite, calcium carbonate, magnesium carbonate, yttrium oxide and zirconium oxide.

[0039] To better illustrate the present invention, the present invention will be further described below with reference to specific embodiments.

[0040] Example 1 The environmentally friendly low-refractive-index corrosion-resistant glass of this embodiment is composed of the following molar percentages: 74.9% SiO2, 4.9% Al2O3, 0.2% MgO, 4.5% Na2O, 1.4% CaO, 8.9% K2O, 4.4% B2O3, 0.2% CeO2, 0.1% CaF2, 0.3% Y2O3, and 0.2% ZrO2.

[0041] The preparation method of the environmentally friendly low-refractive-index corrosion-resistant glass in this embodiment is as follows: Quartz sand, aluminum hydroxide, magnesium carbonate, sodium nitrate, calcium carbonate, potassium carbonate, boric acid, cerium oxide, fluorite, yttrium oxide, and zirconium oxide are used as raw materials. The raw materials are mixed in a specific ratio, and the mixture is melted at 1500℃ with auxiliary stirring for clarification. It is then mechanically drawn at 1230℃ and precision annealed at 550℃ to obtain the final product. Figure 2 As shown.

[0042] The refractive index of the glass samples was tested using a Metricon Model 2010 / M prism coupling tester. During the test, a beam of parallel light was incident perpendicularly onto the incident surface of a V-prism. If the refractive index of the sample matches that of the V-prism, the light will pass through the interface without deflection; if there is a difference, the light will refract. The refractive index of the sample can be obtained by measuring the deflection angle between the incident and outgoing light and calculating it according to the law of refraction. The test was conducted at room temperature, conforming to the requirements of GB / T7962.1-2010 standard.

[0043] The coefficient of linear expansion of glass samples was determined using a Netzsch DIL 402 thermal dilatometer. Samples were pre-processed into cylinders of Φ6 mm × 50 mm, with both ends ground and polished to ensure flatness and parallelism. The temperature was increased at a rate of 5 °C / min, with data acquisition intervals of 20 ms. Temperature versus sample length curves were recorded, and the data were processed using the tangent method to determine the glass transition temperature Tg and expansion softening temperature Tf. The experimental procedure followed GB / T 7962.16-2010 standard.

[0044] The softening point temperature of glass was measured using a PPV-1000 / 1200 plate viscometer manufactured by Orton, USA. The sample was prepared as a Φ6 mm × 6 mm cylinder with smooth, parallel end faces. During testing, the sample was placed between two heat-resistant alloy discs, each 44 mm in diameter and 6 mm thick, connected to the probe rod. Thin platinum sheets, approximately 40 mm in diameter and 0.001 inches thick, were placed between the sample and the upper and lower metal plates to facilitate sample loading and prevent adhesion. The softening point of the glass was determined by monitoring the probe displacement under specific heating conditions. This method was performed according to GB / T 7962.16-2010.

[0045] The environmentally friendly, low-refractive-index, corrosion-resistant glass prepared by the method in this embodiment has a refractive index of 1.47. After being etched with acetic acid solution at pH ≤ 2.9 ± 0.2 for more than 5 hours, it did not exhibit discoloration or peeling. Its glass transition temperature (Tg) is 565℃, its softening temperature (Tf) is 652℃, its softening point temperature (Ts) is 750℃, and its coefficient of thermal expansion is 83.8 × 10⁻⁶. -7 With a temperature of / ℃, it has good processability and adaptability, and can be used as a glass material for the production of optical glass fibers and fiber optic panels. The fiber optic panels prepared also have good corrosion resistance, which can fundamentally meet the requirements of extreme environment applications.

[0046] Example 2 The environmentally friendly low-refractive-index corrosion-resistant glass of this embodiment is composed of the following molar percentages: 74.8% SiO2, 4.0% Al2O3, 0.3% MgO, 4.0% Na2O, 1.0% CaO, 9.9% K2O, 5.2% B2O3, 0.1% CeO2, 0.2% CaF2, 0.1% Y2O3, and 0.4% ZrO2.

[0047] The preparation method of the environmentally friendly low-refractive-index corrosion-resistant glass in this embodiment is as follows: using quartz sand, aluminum hydroxide, magnesium carbonate, sodium nitrate, calcium carbonate, potassium carbonate, boric acid, cerium oxide, fluorite, yttrium oxide and zirconium oxide as raw materials, the glass raw materials are mixed in proportion, the batch is melted at 1520℃, clarified by auxiliary stirring, mechanically drawn at 1250℃, and then precision annealed at 555℃ to obtain the glass.

[0048] The environmentally friendly, low-refractive-index, corrosion-resistant glass prepared by the method in this embodiment has a refractive index of 1.48. After being etched with acetic acid solution at pH ≤ 2.9 ± 0.2 for more than 5 hours, it did not exhibit discoloration or peeling. Its glass transition temperature (Tg) is 563℃, its softening temperature (Tf) is 632℃, its softening point temperature (Ts) is 740℃, and its coefficient of thermal expansion is 82.5 × 10⁻⁶. -7 With a temperature of / ℃, it has good processability and adaptability, and can be used as a glass material for the production of optical glass fibers and fiber optic panels. The fiber optic panels prepared also have good corrosion resistance, which can fundamentally meet the requirements of extreme environment applications.

[0049] Example 3 The environmentally friendly low-refractive-index corrosion-resistant glass of this embodiment is composed of the following molar percentages: 79.5% SiO2, 3.0% Al2O3, 0% MgO, 3.4% Na2O, 1.0% CaO, 8.0% K2O, 4.0% B2O3, 0.3% CeO2, 0.3% CaF2, 0.4% Y2O3, and 0.1% ZrO2.

[0050] The method for preparing environmentally friendly low-refractive-index corrosion-resistant glass in this embodiment is as follows: using quartz sand, aluminum hydroxide, magnesium carbonate, sodium nitrate, calcium carbonate, potassium carbonate, boric acid, cerium oxide, fluorite, yttrium oxide and zirconium oxide as raw materials, the glass raw materials are mixed in proportion, the batch is melted at 1550℃, clarified by auxiliary stirring, mechanically drawn at 1300℃, and then precision annealed at 560℃ to obtain the glass.

[0051] The environmentally friendly, low-refractive-index, corrosion-resistant glass prepared by the method in this embodiment has a refractive index of 1.46. After being etched with acetic acid solution at pH ≤ 2.9 ± 0.2 for more than 5 hours, it did not exhibit discoloration or peeling. Its glass transition temperature (Tg) is 570℃, its expansion softening temperature (Tf) is 650℃, its softening point temperature (Ts) is 760℃, and its coefficient of thermal expansion is 81.7 × 10⁻⁶. -7 With a temperature of / ℃, it has good processability and adaptability, and can be used as a glass material for the production of optical glass fibers and fiber optic panels. The fiber optic panels prepared also have good corrosion resistance, which can fundamentally meet the requirements of extreme environment applications.

[0052] Example 4 The environmentally friendly low-refractive-index corrosion-resistant glass of this embodiment is composed of the following molar percentages: 69.0% SiO2, 7.5% Al2O3, 1.0% MgO, 2.4% Na2O, 1.2% CaO, 9.0% K2O, 7.9% B2O3, 0.3% CeO2, 1.5% CaF2, 0.1% Y2O3, and 0.1% ZrO2.

[0053] The method for preparing environmentally friendly low-refractive-index corrosion-resistant glass in this embodiment is as follows: using quartz sand, aluminum hydroxide, magnesium carbonate, sodium nitrate, calcium carbonate, potassium carbonate, boric acid, cerium oxide, fluorite, yttrium oxide and zirconium oxide as raw materials, the glass raw materials are mixed in proportion, the batch is melted at 1550℃, clarified by auxiliary stirring, mechanically drawn at 1200℃, and then precision annealed at 560℃ to obtain the glass.

[0054] The environmentally friendly, low-refractive-index, corrosion-resistant glass prepared by the method in this embodiment has a refractive index of 1.47. After being etched with acetic acid solution at pH ≤ 2.9 ± 0.2 for more than 5 hours, it did not exhibit discoloration or peeling. Its glass transition temperature (Tg) is 570℃, its softening temperature (Tf) is 650℃, its softening point temperature (Ts) is 760℃, and its coefficient of thermal expansion is 81.7 × 10⁻⁶. -7 With a temperature of / ℃, it has good processability and adaptability, and can be used as a glass material for the production of optical glass fibers and fiber optic panels. The fiber optic panels prepared also have good corrosion resistance, which can fundamentally meet the requirements of extreme environment applications.

[0055] Example 5 The environmentally friendly low-refractive-index corrosion-resistant glass of this embodiment is composed of the following molar percentages: 80.5% SiO2, 6.0% Al2O3, 1.2% MgO, 2.0% Na2O, 0% CaO, 6.0% K2O, 3.5% B2O3, 0.2% CeO2, 0.1% CaF2, 0.2% Y2O3, and 0.3% ZrO2.

[0056] The method for preparing environmentally friendly low-refractive-index corrosion-resistant glass in this embodiment is as follows: using quartz sand, aluminum hydroxide, magnesium carbonate, sodium nitrate, calcium carbonate, potassium carbonate, boric acid, cerium oxide, fluorite, yttrium oxide and zirconium oxide as raw materials, the glass raw materials are mixed in proportion, the batch is melted at 1540℃, clarified by auxiliary stirring, mechanically drawn at 1290℃, and then precision annealed at 558℃ to obtain the glass.

[0057] The environmentally friendly, low-refractive-index, corrosion-resistant glass prepared by the method in this embodiment has a refractive index of 1.46. After being etched with acetic acid solution at pH ≤ 2.9 ± 0.2 for more than 5 hours, it did not exhibit discoloration or peeling. Its glass transition temperature (Tg) is 572℃, its softening temperature (Tf) is 646℃, its softening point temperature (Ts) is 758℃, and its coefficient of thermal expansion is 80.9 × 10⁻⁶. -7 With a temperature of / ℃, it has good processability and adaptability, and can be used as a glass material for the production of optical glass fibers and fiber optic panels. The fiber optic panels prepared also have good corrosion resistance, which can fundamentally meet the requirements of extreme environment applications.

[0058] Example 6 The environmentally friendly low-refractive-index corrosion-resistant glass of this embodiment is composed of the following molar percentage components: 70.0% SiO2, 9.0% Al2O3, 0.8% MgO, 3.2% Na2O, 1.5% CaO, 8.6% K2O, 5.8% B2O3, 0.2% CeO2, 0.5% CaF2, 0.3% Y2O3, and 0.1% ZrO2.

[0059] The method for preparing the environmentally friendly low-refractive-index corrosion-resistant glass material in this embodiment is as follows: using quartz sand, aluminum hydroxide, magnesium carbonate, sodium nitrate, calcium carbonate, potassium carbonate, boric acid, cerium oxide, fluorite, yttrium oxide and zirconium oxide as raw materials, the various glass raw materials are mixed in proportion, the batch is melted at 1480℃, clarified by auxiliary stirring, mechanically drawn at 1210℃, and then precision annealed at 545℃ to obtain the final product.

[0060] The environmentally friendly, low-refractive-index, corrosion-resistant glass prepared by the method in this embodiment has a refractive index of 1.47. After being etched with acetic acid solution at pH ≤ 2.9 ± 0.2 for more than 5 hours, it did not exhibit discoloration or peeling. Its glass transition temperature (Tg) is 550℃, its softening temperature (Tf) is 660℃, its softening point temperature (Ts) is 768℃, and its coefficient of thermal expansion is 85.4 × 10⁻⁶. -7 With a temperature of / ℃, it has good processability and adaptability, and can be used as a glass material for the production of optical glass fibers and fiber optic panels. The fiber optic panels prepared also have good corrosion resistance, which can fundamentally meet the requirements of extreme environment applications.

[0061] Comparative Example 1 The glass material of this comparative example is composed of the following components in molar percentage: 75.1% SiO2, 4.9% Al2O3, 0.2% MgO, 4.5% Na2O, 1.4% CaO, 8.9% K2O, 4.4% B2O3, 0.1% CaF2, 0.3% Y2O3, and 0.2% ZrO2.

[0062] The glass material preparation method of this comparative example is as follows: using quartz sand, boric acid, cerium oxide, sodium nitrate, potassium nitrate, aluminum hydroxide, fluorite, and magnesium carbonate as raw materials, the glass raw materials are mixed in proportion and prepared according to the method of Example 1.

[0063] The testing method is the same as in Example 1. The refractive index of the glass material in this comparative example is 1.54. After being etched with acetic acid solution (pH ≤ 2.9 ± 0.2) for < 5 hours and ≥ 30 minutes, it exhibits violet-blue interference colors, but does not show any discoloration or peeling. Its glass transition temperature (Tg) is 578℃, its softening temperature (Tf) is 654℃, its softening point temperature (Ts) is 780℃, and its coefficient of thermal expansion is 88.2 × 10⁻⁶. -7 / ℃.

[0064] Comparative Example 2 The glass material of this comparative example is composed of the following components in molar percentage: 75.0% SiO2, 4.9% Al2O3, 0.2% MgO, 4.5% Na2O, 1.4% CaO, 8.9% K2O, 4.4% B2O3, 0.2% CeO2, 0.3% Y2O3, and 0.2% ZrO2.

[0065] The glass material preparation method of this comparative example is as follows: using quartz sand, boric acid, cerium oxide, sodium nitrate, potassium nitrate, aluminum hydroxide, fluorite, and magnesium carbonate as raw materials, the glass raw materials are mixed in proportion and prepared according to the method of Example 1.

[0066] The testing method is the same as in Example 1. The refractive index of the glass material in this comparative example is 1.48. After being etched with an acetic acid solution with pH ≤ 2.9 ± 0.2 for < 5 hours and ≥ 30 minutes, it exhibits a violet-blue interference color, but does not show any discoloration or peeling. Its glass transition temperature Tg is 560℃, its expansion and softening temperature Tf is 659℃, its softening point temperature Ts is 770℃, and its coefficient of thermal expansion is 80.1 × 10⁻⁶. -7 / ℃.

[0067] Comparative Example 3 The glass material of this comparative example is composed of the following components in molar percentage: 75.2% SiO2, 4.9% Al2O3, 0.2% MgO, 4.5% Na2O, 1.4% CaO, 8.9% K2O, 4.4% B2O3, 0.2% CeO2, 0.1% CaF2, and 0.2% ZrO2.

[0068] The glass material preparation method of this comparative example is as follows: using quartz sand, boric acid, cerium oxide, sodium nitrate, potassium nitrate, aluminum hydroxide, fluorite, and magnesium carbonate as raw materials, the glass raw materials are mixed in proportion and prepared according to the method of Example 1.

[0069] The testing method is the same as in Example 1. The refractive index of the glass material in this comparative example is 1.57. After being etched with an acetic acid solution with pH ≤ 2.9 ± 0.2 for < 30 min, it exhibits a violet-blue interference color, but does not show any discoloration or peeling. Its glass transition temperature Tg is 557℃, its expansion and softening temperature Tf is 663℃, its softening point temperature Ts is 768℃, and its coefficient of thermal expansion is 85.4 × 10⁻⁶. -7 / ℃.

[0070] Comparative Example 4 The glass material of this comparative example is composed of the following components in molar percentage: 75.1% SiO2, 4.9% Al2O3, 0.2% MgO, 4.5% Na2O, 1.4% CaO, 8.9% K2O, 4.4% B2O3, 0.2% CeO2, 0.1% CaF2, and 0.3% Y2O3.

[0071] The glass material preparation method of this comparative example is as follows: using quartz sand, boric acid, cerium oxide, sodium nitrate, potassium nitrate, aluminum hydroxide, fluorite, and magnesium carbonate as raw materials, the glass raw materials are mixed in proportion and prepared according to the method of Example 1.

[0072] The testing method is the same as in Example 1. The refractive index of the glass material in this comparative example is 1.53. After being etched with an acetic acid solution with pH ≤ 2.9 ± 0.2 for < 30 min, it exhibits a violet-blue interference color, but does not show any discoloration or peeling. Its glass transition temperature Tg is 559℃, its expansion softening temperature Tf is 667℃, its softening point temperature Ts is 765℃, and its coefficient of thermal expansion is 88.7 × 10⁻⁶. -7 / ℃.

[0073] Comparative Example 5 The glass material of this comparative example is composed of the following components in molar percentage: 75.0% SiO2, 5.0% Al2O3, 0.2% MgO, 4.6% Na2O, 1.4% CaO, 9.0% K2O, 4.5% B2O3, 0.2% CeO2, and 0.1% CaF2.

[0074] The glass material preparation method of this comparative example is as follows: using quartz sand, boric acid, cerium oxide, sodium nitrate, potassium nitrate, aluminum hydroxide, fluorite, and magnesium carbonate as raw materials, the glass raw materials are mixed in proportion and prepared according to the method of Example 1.

[0075] The testing method is the same as in Example 1. The refractive index of the glass material in this comparative example is 1.55. After being etched with an acetic acid solution with pH ≤ 2.9 ± 0.2 for < 30 min, it exhibits a violet-blue interference color, but does not show any discoloration or peeling. Its glass transition temperature Tg is 546.5℃, its expansion softening temperature Tf is 648℃, its softening point temperature Ts is 757.5℃, and its coefficient of thermal expansion is 90.2 × 10⁻⁶. -7 / ℃.

[0076] Comparative Example 6 The glass material of this comparative example is composed of the following components in molar percentage: 74.6% SiO2, 4.9% Al2O3, 0.2% MgO, 4.6% Na2O, 1.5% CaO, 9.0% K2O, 4.4% B2O3, 0.2% CeO2, 0.1% CaF2, 0.3% Y2O3, and 0.2% ZrO2.

[0077] The glass material preparation method of this comparative example is as follows: using quartz sand, boric acid, cerium oxide, sodium nitrate, potassium nitrate, aluminum hydroxide, fluorite, and magnesium carbonate as raw materials, the glass raw materials are mixed in proportion and prepared according to the method of Example 1.

[0078] The testing method is the same as in Example 1. The refractive index of the glass material in this comparative example is 1.56. After being etched with an acetic acid solution with pH ≤ 2.9 ± 0.2 for < 5 hours, it exhibits a violet-blue interference color, but does not show any discoloration or peeling. Its glass transition temperature Tg is 567℃, its expansion softening temperature Tf is 657℃, its softening point temperature Ts is 768℃, and its coefficient of thermal expansion is 80.2 × 10⁻⁶. -7 / ℃.

[0079] Using the glass material described in the above embodiment as the cladding glass material, fiber optic tapers are prepared by drawing the glass together with commonly used core materials. This process involves drawing single filaments and multiple multifilaments, arranging the multifilaments regularly, and then melting and pressing them into blank segments. These segments are then sliced, rounded, ground, and polished to prepare corrosion-resistant fiber optic tapers, which are then tested. Specifically, the glass prepared in Example 1 is further used to prepare corrosion-resistant fiber optic tapers. The transmittance at a wavelength of 560 nm before and after etching with an acetic acid solution with pH ≤ 2.9 ± 0.2 is 91.1% and 90.9% respectively (a decrease of 0.2%). Figure 1 As shown.

[0080] Tables 1 and 2 below summarize the glass sample composition and glass properties of the above-described illustrative embodiments and comparative examples of the present invention.

[0081] Table 1. Composition of glass samples from Examples 1-6 and Comparative Examples 1-6

[0082] Table 2. Performance test results of glass samples from Examples 1-6 and Comparative Examples 1-6

[0083] As shown in Table 2, the environmentally friendly, low-refractive-index, corrosion-resistant glass material provided by this invention has a refractive index ≤1.48, a glass transition temperature Tg ≤580℃, an expansion softening temperature Tf ≤670℃, and a softening point temperature Ts ≤775℃. It exhibits good processability and adaptability, and its coefficient of thermal expansion in the range of 20℃ to 300℃ is (80~87)×10⁻⁶. -7 At / ℃, it has good thermal processing performance, which is conducive to the molding and preparation of large-size devices. It is compatible with core glass materials and can be used as skin glass material for the production of optical glass fibers and fiber optic panels. After being etched with acetic acid solution with pH≤2.9±0.2 for more than 5 hours, it did not show any discoloration or peeling. The fiber optic cones prepared also have good corrosion resistance, which can fundamentally meet the requirements of extreme environment applications.

[0084] The various specific technical features described in the above embodiments of the present invention can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An environmentally friendly, low-refractive-index, corrosion-resistant glass, characterized in that, Its composition, by molar percentage, consists of the following components: 68-82% SiO2, 3.5-8% B2O3, 0.1-0.3% CeO2, 8-14% alkali metal oxides, 3-9% Al2O3, 1-5% alkaline earth metal oxides, and 0.1-1.5% CaF2, 0.1-0.5% ZrO2, and 0.1-0.5% Y2O3. The total content of SiO2, Al2O3, and B2O3 in the composition is 84-91%. The alkali metal oxides are selected from Na2O and K2O, and the alkaline earth metal oxides are selected from at least one of CaO and MgO.

2. The environmentally friendly low-refractive-index corrosion-resistant glass as described in claim 1, characterized in that, The molar content of SiO2 is 68~82%, 68~80%, 68~78%, 68~76%, 68~74%, 68~72%, 68~70%, 70~72%, 68~75.1%, 68~70.7%, 68~69.8%, 70.7~72.7%, 68~72.7%, or 70.7~82%. Alternatively, the molar content of B2O3 is 3.5~4.5%, 3.5~7.9%, 3.5~7%, 4~5.2%, 4~8%, 5.2~7.2%, 5.2~7.9%, 5.2~7%, 7~8%, 4.1~4.7%, 4.5~7.9%, 7.2~8%, 5.2~6.8%, 6.9~7.2%, 7.2~7.8%; Alternatively, the molar content of Al2O3 is 3~3.9%, 3~4.9%, 3.9~7%, 3.1~5.1%, 3.1~5.9%, 4.9~7%, 4.9~5.1%, and 5.1~7%, 3.1~4.1% or 4.1~7%. Alternatively, the total molar content of SiO2, Al2O3 and B2O3 is 84~86%, 86~88% or 88~91%.

3. The environmentally friendly low-refractive-index corrosion-resistant glass as described in claim 1, characterized in that, The molar content of CeO2 is 0.1~0.2% and 0.2~0.3%. Alternatively, the molar content of CaF2 is 0.1~1.5%, 0.1~1.2%, 0.1~1.0%, 0.1~0.8%, 0.2~0.3%, 0.2~0.5%, 0.2~0.8%, 0.1~0.2%, 0.1~0.3%, 0.9~1.5%, 0.2~1.5%, or 0.3~1.5%.

4. The environmentally friendly low-refractive-index corrosion-resistant glass as described in claim 1, characterized in that, The molar content of alkali metal oxides is 8-10%, 10-12%, or 12-14%; Alternatively, the molar content of Na2O is 2-5%, and the molar content of K2O is 6-12%; Alternatively, the molar content of Na2O may be 2-5%, 2-4%, 2-3%, 3-5%, or 4-5%. Alternatively, the molar content of K2O is 6~8.3%, 6~6.9%, 6.9~9%, 6~9%, 6.3~9%, 7~9%, 8~9%, or 9~12%.

5. The environmentally friendly low-refractive-index corrosion-resistant glass as described in claim 1, characterized in that, The molar content of Y2O3 is 0.1~0.4%, 0.1~0.3%, 0.1~0.2%, 0.2~0.3%, 0.2~0.4%, and 0.2~0.5%. Alternatively, the molar content of ZrO2 is 0.1~0.4%, 0.1~0.3%, 0.1~0.2%, 0.2~0.3%, 0.2~0.4%, or 0.2~0.5%.

6. The environmentally friendly low-refractive-index corrosion-resistant glass as described in claim 1, characterized in that, The molar content of MgO is 0~1.5%, 0~0.5%, 0.1~0.5%, 0.1~0.3%, 0.2~0.5%, and 0.5~1.5%. Alternatively, the molar content of CaO is 0~1.6% or 1~1.6%; Alternatively, the molar content of alkaline earth metal oxides is 1.3~2%, 1.5~2%, 1.3~1.9%, or 2~5%.

7. The environmentally friendly low-refractive-index corrosion-resistant glass as described in claim 1, characterized in that, Its refractive index is ≤1.48; Alternatively, if Tg≤580℃, Tf≤670℃, Ts≤775℃, the coefficient of thermal expansion in the range of 20℃~300℃ is (80~87)×10. -7 / ℃.

8. A method for preparing the environmentally friendly low-refractive-index corrosion-resistant glass according to claim 1, characterized in that, Includes the following steps: The raw materials are mixed in proportion, and the mixed raw materials are then melted at high temperature, stirred to help clarify and homogenize, drawn into shape and annealed.

9. The preparation method according to claim 8, characterized in that, The high-temperature melting temperature is 1350~1550℃, the drawing temperature is 1050~1350℃, and the annealing temperature is 500~600℃; Alternatively, the raw materials may include: quartz sand, boric acid, cerium oxide, sodium salt, potassium salt, aluminum source, fluorite, barium salt, calcium carbonate, magnesium carbonate, yttrium oxide, and zirconium oxide; wherein the sodium salt is sodium carbonate or sodium nitrate, the potassium salt is potassium carbonate or potassium nitrate, the aluminum source is aluminum hydroxide or aluminum oxide, and the barium salt is barium nitrate or barium carbonate.

10. The application of the environmentally friendly low-refractive-index corrosion-resistant glass according to any one of claims 1 to 7 in the skin glass or optical glass fiber for optical cones.

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