Optical quartz glass is a synthetic, high-purity fused silica produced by a flame hydrolysis melting process. The crystal-clear amorphous material contains virtually no impurities, consisting only of silicon and oxygen (silicon dioxide). This unique type of quartz glass provides over 80% UV light transmission at a wavelength of 185 nm.
The enormous temperature range and thermal endurance of quartz glass are unparalleled. It can operate continuously up to 1000 °C and is highly resistant to thermal shock due to its very low coefficient of thermal expansion. As well, the chemical properties of quartz glass are remarkable. Its chemical resistance to acids exceeds that of almost all other glass types. Quartz glass is durable and exceptionally resistant to salt solutions, alkalis, and water.
Due to its excellent electrical properties, quartz glass is also ideal for solutions in semiconductor technology. Because currents can only flow through mobile ionic impurities that are marginally present in quartz glass, it offers exceptionally high electrical insulation, which is essential for the fabrication of many electronic devices and semiconductors.
We manufacture custom optics for the UV, visible, and infrared wavelength ranges, primarily from large quartz blocks called boules. We can select the raw glass for low inclusions and bubbles. In addition, an index homogeneity of up to ≤ 0.5 ppm is available if this is a critical requirement for an application. Cutting the raw glass from the boule is the first step in the production of a quartz glass optic. After this process, the quartz glass is shaped, finely ground, and polished according to the specific surface requirements. In this way, our company produces UV-transparent substrate glasses, glass wafers, microscope slides, high-quality custom optics, and many other quartz glass products daily.
To request a quotation for windows, substrates, glass plates, or other optical quartz glass parts with individual dimensions, please select a thickness from the table or use the button below.
Specifications and Properties
Transmittance spectrum of synthetic
fused silica in the ultraviolet-to-infrared rangeGlass Thicknesses
As high-purity fused silica is a block glass, there are usually no off-the-shelf standard thicknesses available. The thickness must be individually specified and manufactured. However, we continuously grind and polish to different thicknesses and tolerances to offer our customers the best possible availability and short lead times. You can even order these with individual dimensions and take advantage of our 48-hour express production.
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Glass THK |
Tolerance |
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---|---|---|
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 | ✔ |
Other thicknesses are possible on demand. |
Light Transmission
- T > 80% at 185 nm
Refractive Index
- nd = 1.4585
Density
- 2.20 g/cm3
Young's Modulus
- 74 GPa (typical value)
Homogeneity
- Homogeneity classes per specification, if required
- Index homogeneity down to ≤ 0.5 ppm is possible on demand
Inclusion Classes
- Inclusion-class options are available
Glass Composition
- Silicon Dioxide (SiO2)
Operating Temperature
- Up to 1000 °C
Average Coefficient of Thermal Expansion
- ≈ 0.57 × 10-6/K
Viscosity
- Softening point: ≈ 1585 °C
- Annealing point: ≈ 1042 °C
- Strain point: ≈ 893 °C
Dielectric Constant
- εr: 3.9 (500 MHz)
Fused Quartz for Sight Glass Applications
In addition to the optical quartz glass described above, we also process a less sophisticated quartz type called fused quartz. Although this product is also commonly called quartz glass, it is clearly different. Unlike fused silica, this material is made by melting natural quartz crystals. As a result, it contains far more impurities and can't offer the homogeneity or outstanding optical performance of fused silica. These lower material grades are typically used for high-temperature applications where only sight glass quality is needed. As purity and deep UV transparency are of secondary importance in such use cases, this more economical quartz glass type is often the best choice for such components. Although fused quartz glass is only suitable for less demanding applications, it has an almost identical coefficient of expansion, a similar heat resistance, and the same interesting thermal properties as the higher-grade materials. It also offers excellent chemical resistance and better UV-light transparency than most other glasses. Furthermore, it is capable of high infrared transmission and has the same crystal-clear appearance as optical quartz.
Fused quartz is typically used for the fabrication of high-temperature sight glasses, lamp housings, UV lighting or disinfection systems, clear furnace glasses, pressure-resistant windows, and other quartz glass components. For further details, specifications, and properties, please refer to our fused quartz datasheet.
Our company processes raw materials from leading manufacturers in the quartz glass industry (Corning, Heraeus, Tosoh, SCHOTT, Saint-Gobain Quartz, Shin-Etsu, GE Quartz, and many others). More detailed properties, datasheets, and information on all glass qualities we process are available on request.
All details and specifications given are average reference values and are not guaranteed. Please consider the "Notes on technical specifications".
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Last update: February 07, 2025