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Zero expansion titania-silicate glass 7972

Special Properties

  • Ultra-low thermal expansion
  • Very high-temperature shock resistance
  • High operating temperature
  • Available in large dimensions
  • Non-crystalline, amorphous glass (no ceramic)

Typical Applications

  • Low expansion glass substrates
  • Length standards
  • Lightweight honeycomb mirror mounts
  • Glass scales for CNC machines
  • Solid and lightweight mirror blanks
  • Astronomical telescopes
  • Precision measurement technology
  • Satellite applications in space
  • Laser cavities
  • Precision gyroscopes

Related products

  • ZERODUR® (zero expansion transparent glass-ceramic)

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ULE® titania-silicate glass is a zero expansion material made by a flame hydrolysis process. The amorphous ULE® raw glass materials from CORNING come in large and unshaped glass blocks, the so-called "boules", which allow the manufacturing of components with almost any shape or dimension. At room temperature, the glass material has a coefficient of thermal expansion close to zero.

Through its ultra-low length expansion, ULE® guarantees dimensional stability even under thermally unstable conditions. The homogeneity of the thermal expansion of standard Grade ULE® glass within each boule is typically less than 15 ppb/°C radially and axially. Even lower expansion grades and detailed information about these material qualities are available on request. Those materials can offer even higher homogeneity in the coefficient of thermal expansion. The CTE of ULE® glass is measured by a non-destructive ultrasonic test method.

The ULE® material is a perfect choice for various applications in space and astronomy. It is also used in precision mechanical machines, lasers, and laser cavities. Besides, reference length standards for CNC machines are often made of ULE® glass. Due to its extraordinary properties, ULE® material is also perfect for many scientific applications. We fabricate components ranging from a few millimeters up to meters from this unique glass material.

ULE® has the optical clarity and chemical resistance expected from glass. Furthermore, it provides a very high degree of thermal shock resistance, enabling breakthrough technology in optical fiber techniques for medical applications. No measurable hysteresis is exhibited after heavy thermal cycles. When ULE® materials are heated to 350 °C and then quenched with water, there is no residual detectable figure change.

To request a quotation for your component or optics made of original CORNING ULE® ultra-low expansion glass with individual dimensions, please click the button below:


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Optical Properties

Show the transmission of ULE® low expansion glass

  • Refractive Index (nominal CTE material):
    • nF = 1.4892 (486 nm)
      nD = 1.4828 (589 nm)
      nC = 1.4801 (656 nm)
  • Abbe number: vd= 53.1
  • Stress optical coefficient: 4.15 (nm/cm)/(kg/cm2)
  • dn/dt:
    • 10.68 × 10-6/°C (20–40 °C)
    • 11.24 × 10-6/°C (40–60 °C)

Mechanical properties

  • Density (ρ): 2.21 g/cm3 (25 °C)
  • Elastic Modulus (E): 67.6 GPa
  • Bulk Modulus (K): 34.1 GPa
  • Shear Modulus (G): 29.0 GPa
  • Specific stiffness (E/ρ): 3.12 × 106 m
  • Ultimate Tensile Stress (MOR): 49.8 MPa
  • Knoop Hardness: 460 kg/mm2 (200 g load)
  • Poisson's Ratio (v): 0.17

Thermal Properties

  • Mean linear coefficient of thermal expansion (α):
    0 ± 30 × 10-9/K (5 - 35 °C ; 95% confidence level)
  • Show the typical curve of thermal expansion
  • Softening Point: 1490 °C (estimated)
  • Annealing Point: 1000 °C
  • Strain Point: 890 °C
  • Thermal conductivity (K): 1.31 W/(m × °C)
  • Thermal diffusivity (D): 0.079 cm2/s
  • Mean specific heat (Cp): 767 J/(kg x °C)

Standard Grade Material Specifications:

  • Maximum CTE variation: 15 ppb/°C (Radial & Axial)
  • Birefringence: 20 nm/cm
  • Inclusion chart on request
  • Specifications for Premium Grade, Mirror Grade, and Tooling Grade material quality are available on request

Chemical Properties

(at 95 °C)

Duration of Test

Weight Loss

5% HCl
< 0.01
5% NaOH
0.02N Na2CO3
5% H2SO4
< 0.01
< 0.01

Electrical Properties

  • Dielectric Constant : 3.99 (100 Hz ; 25 °C)
  • Loss Factor : 0.00005 (100 Hz ; 25 °C)
  • DC-volume resistivity: 1011.6 Ω × cm


Surface Quality


All given details and specifications are mean reference values and are not guaranteed. Also, please consider our "Notes on technical specifications".


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Last update: May 21, 2024