Corning Glass ULE®

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Since 1947, we have been a precision machining and polishing fabricator of parts from all technical ceramics, sapphire, glass and quartz. We machine these materials to very precise tolerances (many times measured in millionths of an inch) for dimension, flatness, wedge and roundness or cylindricity. Our customers typically have a critical application that requires extremely tight tolerances in ultra-hard materials. We also have the capability to grind and polish spherical radius parts in a variety of hard materials, both inside and outside diameters, to optical requirements.

Please feel free to navigate to other pages within our site to see more information on all of our high precision machining services, materials and capabilities. If you would like more information please click here to send a request, or visit our Frequently Asked Questions page.

ULE® is an ultra-low-expansion glass with a very low coefficient of thermal expansion.

Ultra-low expansion glass (ULE) is a glass material made by Corning Glass Company that is designed and formulated to exhibit essentially zero thermal expansion over a wide temperature range. ULE is totally amorphous without crystal phases.

The essentially near zero thermal expansion is useful where precision parts will face thermal variation in application. An ideal application is as a mirror substrate for astronomical telescopes, any precision measurement tooling or reference fixtures, as well as spacers for some laser assemblies. High resistance to thermal expansion makes it very resistant to high temperature thermal shock, which can be of benefit to the semiconductor industry.

ULE 7972 is a titania-silicate glass with less than 10% titanium dioxide that is transparent with no color. Precision parts are machined using a diamond grinding process, and parts can then be optically polished as necessary using chemo-mechanical methods. This material is also sometimes specified for extreme UV applications.

Since 1947, Insaco has had many years’ experience fabricating precision parts from this material to exacting customer requirements. The material is readily available in bulk. ULE is a registered trademark of Corning Glass, and since it is a proprietary material, where absolute material properties are critical to the application, it is best to contact the producer’s website directly to understand availability. For smaller precision parts, Insaco is able to source commercial material in its best form and then fabricate it to customer requirements. We are also willing and able to fabricate from customer supplied material if preferred.

Other Glass Ceramics:

2.2 gm/cc

49 Knoop

Modulus of Elasticity

9.8 x 106 psi

Poisson's Ratio
Dielectric Constant
4 (@ 1 MHz)
Volume Resistivity

1011 ohm-cm

Coefficient of Thermal Expansion

0.00 +/- 0.03 x 10-6/°C

Thermal Conductivity
1.31 W/mK
Specific Heat
0.18 cal/g °C
Maximum Working Temperature
800 °C
Index of Refraction


All properties are at room temperature unless otherwise noted.

Engineering data are representative, and are not intended as absolute nor warrantable. Manufacturer’s Data shown is blended from multiple sources and therefore illustrates the marketplace.

*Click on a Property to see a comparison of up to 10 materials