Quartz Glass

Special Properties

• Excellent ultraviolet light transmission
• Very high purity
• Outstanding optical performance
• Operating temperature of up to 1000 °C
• Low coefficient of thermal expansion
• Amorphous (non-crystalline) structure
• Crystal-clear appearance
• Very high thermal shock resistance
• Exceptional chemical strength
• High hardness and good scratch resistance
• Good electrical insulation properties
• Low fluorescence
• Made by a flame hydrolysis process
• Superb mechanical properties
• Machinable by CNC cutting, grinding, and polishing

Typical Applications

• UV and laser optics
• Substrates for mirrors and filter coatings
• Measuring instruments for the UV spectrum
• Wafers and Photomask blanks for the semiconductor industry
• Microscope slides and cover glasses for medical use
• Components for high-temperature equipment
• Industrial automation
• Laboratory test glasses
• Sample-storage solutions
• Space and aviation applications

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Related Glass Materials

• Fused Quartz
  (Natural fused quartz glass)
• BOROFLOAT^®
  (High-temperature borosilicate glass from SCHOTT)

Optical Quartz Glass—Synthetic Fused Silica

Synthetic fused silica is the most commonly used quartz glass type for optics. It is composed of silicon dioxide (SiO₂), produced by flame hydrolysis by melting extremely pure raw materials. This crystal-clear, amorphous glass is virtually free of inclusions. It consists exclusively of silicon and oxygen and provides the exceptional purity and internal quality required for the manufacture of the most demanding optics.

Superb UV Transmission

Because no metals or other contaminants that typically absorb UV light are present in this high-purity material, optical quartz glass offers high transmission at deep ultraviolet wavelengths. At 185 nm, for example, its transmission is greater than 80%. The structure of the pure silicon dioxide in synthetic quartz glass is extremely homogeneous, which further minimizes absorption and scattering losses in the UV. This makes it the preferred material for many applications in the ultraviolet spectrum.

Exceptional Thermal Performance

Synthetic quartz glass exhibits outstanding heat resistance, primarily due to its small coefficient of thermal expansion (CTE). It can withstand temperatures up to 1000 °C or higher. Its superb thermal shock stability allows rapid heating or cooling without cracking, making it particularly valuable for applications in the semiconductor industry and aerospace.

High Chemical Strength

Quartz glass has remarkable chemical properties. Its strength against acids surpasses that of most other glasses. Only phosphoric acid and hydrofluoric acid are capable of attacking quartz glass. In addition, optical quartz glass is resistant to salt solutions, water, and reactive gases. Its chemical stability ensures long-term durability in environments where other glasses would deteriorate, making it an ideal choice for demanding and corrosive conditions.

Special Electrical Properties

Quartz glass is widely recognized for its outstanding insulating properties. Because mobile ionic impurities are almost absent, quartz glass has exceptionally high insulation resistance. It is an excellent insulator even under elevated thermal conditions. The material also features a low dielectric constant and maintains stable dielectric properties across a wide range of frequencies, including the gigahertz range. These properties make optical quartz glass a preferred material for high-voltage, high-frequency, and precision electronic applications.

Optics Made of Quartz Glass

We produce quartz optics for the ultraviolet, visible, and infrared spectra, starting with high-purity blocks known as boules, which can be selected for minimal inclusions and bubbles. If required by your application, we can achieve refractive index homogeneity as low as ≤ 0.5 ppm. The first step in manufacturing a quartz glass optic is cutting the material from the boule. After cutting, the material is shaped and polished to meet specific requirements for flatness and surface quality. This process enables us to manufacture many quartz optics daily, including UV-transparent windows, wafers, microscope slides, quartz plates, and various other quartz glass components.

Quartz Glass FAQ
Choosing the right quartz material

Selecting the appropriate quartz glass for a specific application can be challenging due to the variety of grades and their differing properties and costs. Our Quartz Glass FAQ page provides guidance to help you select the appropriate material.

To request a quote for optical quartz glass parts with custom dimensions, please select your desired material from the options provided in the table or click the button below.

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48-hour express manufacturing

Specifications

Ultraviolet to infrared transmission
at 160–5000 nm, 10 mm thick

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Typical transmission
at 185–700 nm, 1 mm thick

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Standard Thicknesses

Since high-purity quartz glass is delivered in unprocessed glass blocks, there are usually no standard thicknesses. Therefore, a required thickness must typically be specified and manufactured to order. To offer our customers the best possible availability and short delivery times, we continuously grind and polish quartz glass to some common thicknesses and tolerances, all featuring high-quality optical finishes. These thicknesses can therefore be ordered with individually specified dimensions and short delivery times:

Thickness (mm)	Tolerance
0.175	±0.020	✔
0.30	±0.050	✔
0.30	±0.025	✔
0.50	±0.050	✔
0.50	±0.030	✔
0.50	±0.025	✔
1.00	±0.100	✔
1.00	±0.025	✔
1.10	±0.100	✔
2.00	±0.150	✔
3.00	±0.200	✔
3.00	±0.025	✔
If you require other thicknesses, please send us your inquiry.

 

Transmission

• T > 80% at 185 nm
  

Refractive index

• n_d = 1.4585

Density

• 2.20 g/cm³

Young's modulus

• 74 GPa (typical value)

Homogeneity

• Homogeneity classes per specification
• Index homogeneity down to ≤ 0.5 ppm is possible on demand

Inclusion classes

• Inclusion-class options on demand

Glass composition

• Silicon dioxide (SiO₂)

Operating temperature

• Up to 1000 °C

Average coefficient of thermal expansion

• ≈ 0.57 × 10^-6/K

Viscosity Temperatures

• Softening point: ≈ 1585 °C
• Annealing point: ≈ 1042 °C
• Strain point: ≈ 893 °C

Dielectric constant

• ε_r: 3.9 (500 MHz)

 

Fused Silica is not the same as Fused Quartz

In addition to the high-purity quartz glass for optics described in this data sheet, we also offer a less sophisticated type known as natural quartz glass or fused quartz. Although the names are similar, the materials are quite different. Fused quartz glass contains significantly more impurities than synthetic fused silica because it is made by melting naturally occurring quartz crystals from silica sand. While fused quartz glass also has a crystal-clear appearance, it transmits less light in the ultraviolet range but is significantly more economical than fused silica. Although it is generally not suitable for demanding optical or laboratory applications that require high purity, fused quartz is an ideal choice for industrial high-temperature sight glasses, lighting equipment, and situations that require good chemical strength and heat resistance. For more details, please refer to our fused quartz data sheet.

 

Quartz glass materials from all leading manufacturers worldwide

Our company works with non-crystalline quartz glasses from nearly all major suppliers in the industry, including CORNING, Heraeus, Tosoh, SCHOTT, Saint-Gobain Quartz, Shin-Etsu, GE Quartz, and many others. If you are looking for different quartz glass types or require detailed properties, data sheets, and information about the quartz glasses we process, please consider using our request form or email us.

 

All details and specifications provided are average reference values and are not guaranteed. Please refer to the notes on technical specifications for further information.

© 1994–2025 Präzisions Glas & Optik GmbH

Last update: October 7, 2025