Quartz Glass FAQ

How to select the suitable quartz glass grade for projects?The core of selection is to combine the working spectral band and actual working environment. If your project focuses on deep ultraviolet transmission such as UV lithography and ultraviolet detection, JGS1 is the preferred option. For conventional visible light and near-ultraviolet optical equipment, JGS2 can fully meet the requirements. If the equipment works in the infrared band, JGS3 with optimized infrared performance is the best choice. For semiconductor production lines with ultra-high purity requirements, synthetic fused silica is a must. We suggest providing detailed working conditions, spectral parameters and usage environment, and our technical team will recommend the most cost-effective solution. What are the key points for quartz glass machining?Quartz glass has high hardness and brittleness, so the processing requirements are much stricter than ordinary glass. Cutting and grinding must adopt professional diamond tools. For semiconductor-grade high-precision optical parts, CMP chemical mechanical polishing is used to achieve sub-nanometer surface roughness. After machining, annealing treatment is indispensable to release internal stress and prevent cracking during later use. For ultra-high purity products used in semiconductors, the whole processing process needs to be completed in a dust-free clean room to avoid surface contamination. Meanwhile, we support customized processing according to customer drawings, samples and special technical indicators.

A: We provide quartz glass with three differentiated purity levels, tailored to distinct industrial standards, optical performance demands and semiconductor manufacturing cleanliness requirements, covering low-cost conventional equipment, precision optical instruments and ultra-clean wafer processing scenarios respectively. 1. Industrial Purity Grade Quartz GlassThis entry-level grade features a silica content of minimum 99.95%, with controlled trace metal impurities at ppm levels. It is widely applied in conventional high-temperature furnaces, infrared heating tubes, boiler sight glass, laboratory general reaction vessels and ordinary mechanical processing parts. The material balances stable heat resistance and cost efficiency, with loose restrictions on internal hydroxyl content and tiny air bubbles, fully meeting non-precision industrial operating standards. It supports common cutting, grinding and bending machining without strict ultra-clean production environment demands.2. Optical Purity Grade Quartz GlassOur optical grade quartz covers JGS1, JGS2 and JGS3 standard series with high silica purity above 99.99%. We precisely regulate internal hydroxyl (-OH) concentration, micro-defects and bubble distribution according to customer-specified spectral transmission bands, ranging from deep ultraviolet to infrared wavelength ranges. JGS1 far UV optical quartz delivers outstanding transmittance under 200nm UV light for UV lithography windows and UV detection lenses; JGS2 UV-visible quartz suits precision optical instruments, spectrometer parts and laboratory optical observation windows; JGS3 infrared quartz maintains stable light penetration in mid-infrared bands for thermal imaging and infrared testing equipment. Every optical blank undergoes full-spectrum transmittance inspection before finishing to guarantee uniform imaging performance.3. Semiconductor Ultra-High Purity Grade QuartzThis is our top-tier purity standard, with silica content reaching 99.999%. All metallic impurity elements including sodium, aluminum, potassium, iron and calcium are strictly controlled at ppb trace levels. We adopt vacuum melting and ultra-clean manufacturing workshops to minimize internal hydroxyl groups, micro-cracks and particle inclusions. It is specially customized for wafer diffusion furnaces, etching equipment, wafer carriers and semiconductor wafer processing chambers. Ultra-low impurity release effectively prevents ion contamination during high-temperature chip production, avoiding circuit short-circuit or performance attenuation caused by metal ion precipitation. This grade complies with global semiconductor fab cleanliness and high-temperature long-cycle service standards. All three grades of quartz glass pass unified multi-step quality inspection before delivery, including purity chemical analysis, spectral transmittance testing, high-temperature aging verification and surface defect scanning. We can also customize transitional intermediate purity quartz materials according to customers’ special technical indicators to match unique production line parameters and budget plans.

A: Quartz glass has an ultra-low linear expansion coefficient of only 5.5×10⁻⁷/°C, giving it excellent anti-quenching ability. Certified products can resist temperature alternations with a 1000°C temperature difference without cracking or deformation. A typical test: heating quartz sheet to 1100°C then quenching in room-temperature water will not break the product, an advantage ordinary heat-resistant glass cannot match.4. How Purity & Hydroxyl Affect Temperature ResistanceHydroxyl (-OH) impurities are the key factor that changes high-temperature performance: High OH quartz (800ppm): Long-term temperature drops 30–50°C, prone to devitrification above 1100°C Medium OH electric-melt quartz (100–300ppm): Balanced cost and heat resistance, standard 1100°C long-term limit Ultra-low OH synthetic quartz (≤10ppm): Stable at 1200°C long-term, little performance loss after hundreds of thermal cycles Excess metal impurities like sodium and aluminum will also accelerate surface crystallization at high heat and lower the usable temperature ceiling. 5. JGS Grade Temperature Parameter Reference JGS1 Far UV Synthetic Quartz: Long-term 1150–1200°C, short peak 1400°C, for UV lithography & semiconductor high-temp windows JGS2 UV-VIS Synthetic Quartz: Long-term 1100–1150°C, short peak 1350°C, for lab furnace sight glass & precision thermal instruments JGS3 Infrared Electric-Melt Quartz: Long-term 1100°C, short peak 1300°C, for infrared heating equipment 6. Practical Usage Tips Vacuum working environment: Reduce long-term allowable temperature by 50–100°C to avoid silica volatilization Avoid direct contact with molten alkali metal above 900°C, chemical corrosion will shorten service life Slow cooling (≤5°C/min) after high-temperature operation to prevent thermal shock cracks To sum up, the universal industrial temperature resistance standard of quartz glass is 1100–1200°C for long continuous work, 1300°C for short transient heating. The actual usable temperature is adjusted by material grade, purity, atmosphere and thermal cycle frequency.

A1: They are standard optical quartz grades. JGS1 for deep UV, JGS2 for conventional UV & visible light, JGS3 for infrared applications. ：Optical Quartz Grades JGS1 JGS2 JGS3Detailed Explanation JGS1, JGS2 and JGS3 are internationally recognized standard grades for optical fused quartz glass, classified mainly by spectral transmittance range and hydroxyl (OH) content. Each grade is engineered for specific light bands and working environments. 1. JGS1It features ultra-low hydroxyl content and the widest transmission range from 160 nm to 2500 nm. It delivers outstanding transmittance for deep ultraviolet (deep UV) light below 220 nm and has strong resistance to UV aging.Typical uses: Deep UV lithography, high-precision UV spectrometers, aerospace UV optical windows and professional deep UV laboratory equipment.2. JGS2With low hydroxyl content, its transmission spectrum covers 220 nm to 2500 nm. It performs well across conventional ultraviolet and visible light bands, and balances stable performance and cost. It is the most cost-effective general-purpose grade.Typical uses: UV sterilization lamps, UV curing systems, general laboratory optical instruments and civil UV optoelectronic products.3. JGS3This grade has medium hydroxyl content and a transmission range of 260 nm to 3500 nm. It is optimized to reduce infrared absorption, achieving superior transmittance in long-wave infrared bands.Typical uses: Infrared thermal imaging cameras, infrared detection systems, high-temperature infrared observation windows and industrial infrared temperature measurement devices.   Concise Extended Version (for embedded FAQ block) JGS series optical quartz is graded by spectral performance: - JGS1: 160nm~2500nm, ultra-low OH group, exclusive for deep UV applications.- JGS2: 220nm~2500nm, balanced performance for regular UV and visible light, widely used for general UV equipment.- JGS3: 260nm~3500nm, low infrared absorption, specially designed for infrared transmission and thermal imaging.

Product Classifications & JGS Optical GradesQ4: How many types of quartz glass are there? What are JGS1, JGS2 and JGS3?A: Quartz glass has two mainstream classification methods, divided by manufacturing process and optical grade respectively. Classified by production craft, there are four main categories. Synthetic fused silica features ultra-high purity for high-end optics and semiconductors. Electrically fused quartz has low hydroxyl content and stable performance under high temperature. Gas-fused quartz is cost-effective and widely used in general industrial occasions. Opaque quartz glass contains tiny air bubbles inside, mainly used for heat insulation.The JGS series is the standard optical grade widely recognized in the industry. JGS1 is the far-ultraviolet grade with high OH content, its deep ultraviolet transmittance is top-tier, with a cut-off wavelength of about 170 nm, mainly applied to UV lithography and spectral analysis instruments. JGS2 is the universal UV-visible grade, with a cut-off wavelength of around 220 nm, which is the standard choice for laboratory utensils and conventional optical components. JGS3 is dedicated to infrared scenarios, with low OH content, optimized for the spectral range of 260 nm to 3000 nm, and commonly used in infrared spectroscopy and thermal imaging devices.

Q3: What fundamental differences exist between quartz glass and common soda-lime glass?A: Ordinary soda-lime glass is the most common glass for daily use, while quartz glass belongs to high-performance special glass. The gaps between them are reflected in composition, heat resistance, optical performance, chemical stability and production process. In terms of chemical composition, ordinary glass contains only 70% to 75% silicon dioxide, and a large amount of soda ash, lime and other additives are added to reduce the melting temperature. In contrast, quartz glass is almost purely composed of silica. When it comes to thermal performance, ordinary glass will gradually soften at around 600°C, and it is very easy to crack when encountering rapid temperature changes. Quartz glass can work continuously at 1100°C to 1200°C, and its thermal expansion coefficient is nearly zero, so it can withstand drastic cold and hot impact. For optical performance, ordinary glass cannot transmit ultraviolet light below 300 nm, while quartz glass realizes full-spectrum transmission from deep UV to infrared. Chemically, quartz glass is resistant to erosion by most acids and organic solvents, while ordinary glass is vulnerable to corrosion by alkaline substances. Besides, the production of quartz glass needs to reach over 2000°C, which puts forward higher requirements on production equipment and technology. ：Quartz Glass vs Borosilicate Glass

Q2: What is the difference between fused silica and fused quartz?A: These two names are frequently used interchangeably in the industry, but they are distinguished by raw materials, production technology, internal composition and practical performance, and are suitable for completely different application scenarios.AspectFused Silica (Synthetic)Fused Quartz (Natural)Raw MaterialMade from synthetic silicon compounds through flame hydrolysis or CVD technologyProcessed from natural high-purity quartz crystals and silica sandPurity LevelUltra-high purity, metallic impurities are controlled at ppb levelHigh purity, impurities stay at ppm level, slightly lower than synthetic typeOH Content1000–2000 ppmLess than 5–30 ppm after vacuum or electric meltingOptical FeatureExcellent deep ultraviolet transmission, the cut-off wavelength is about 170 nmBetter infrared transmission performance, relatively weak in deep ultraviolet bandMain UsageSemiconductor lithography equipment, deep UV laser optical componentsInfrared optical systems, long-term high-temperature industrial structural partsIn actual procurement and design, engineers will select materials strictly according to the spectral requirements and working environment of the equipment to avoid performance mismatch. ：Fused Silica vs Fused Quartz

A: Quartz glass, also universally known as fused silica or fused quartz, is a special amorphous inorganic glass material produced by melting high-purity silica raw materials at an ultra-high temperature above 2000 degrees Celsius. Its main chemical composition is silicon dioxide, with the content reaching no less than 99.95%. Different from traditional crystalline quartz, it has no fixed crystal structure, which endows it with a series of excellent comprehensive properties. It can stably transmit light in ultraviolet, visible light and infrared full spectral bands, and owns extremely low thermal expansion coefficient, outstanding high temperature resistance and strong chemical inertness. Thanks to these advantages, quartz glass has become an indispensable core material in high-end optical systems, semiconductor manufacturing, precision laboratory equipment, high-temperature industrial furnaces and many other high-tech fields. Our company provides standard and customized quartz glass parts covering tubes, plates, rods, windows and various machined components to meet diversified technical demands from global clients. What Is Quartz Glass?