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Titania silicate zero expansion glass 7972

Special Properties

  • Ultra low thermal expansion
  • Very high temperature shock resistance
  • High operating temperature
  • Also available at very large sizes

Typical Applications

  • Ultra low expansion glass substrates
  • Length standards
  • Lightweight honeycomb mirror mounts
  • Machine tool reference glass blocks
  • Solid and lightweight mirror blanks
  • Astronomical telescopes
  • Precision measurement technology
  • Space satellite applications
  • Laser cavities
  • Precision gyroscopes

The zero expansion Titania Silicate glass ULE® is made by flame hydrolysis. ULE® raw glass materials from CORNING come in large glass blocks (boules), which allow the manufacturing of components with almost any shape or dimension. The glass material is characterized by almost zero-expansion at room temperature. By its ultra low thermal coefficient of expansion, ULE® guarantees dimensional stability 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. Higher grade materials and detailed information about those material grades are available on request. They provide an even better CTE (Coefficient of Thermal Expansion) homogeneity. The CTE of ULE® glass is measured by a non-destructive ultrasonic test method.

ULE® material is used for various applications in space technology, astronomy, precision mechanical machines, lasers and laser cavities. Also reference length standards for CNC-machines are often made of ULE® glass. In scientific applications, the material is used due to its interesting properties. Components with dimensions of only some millimeters up to several meters can be fabricated from this extraordinary glass material. ULE® has the excellent optical clarity and chemical resistance which usually is expected of a glass. Furthermore its ultra low CTE provides a very high degree of thermal shock resistance which enables break through technology in optical fiber techniques for medical applications. No measurable hysteresis is exhibited after heavy thermal cycles. When ULE® glass is heated to 350 °C and then quenched with water, there is no residual detectable figure change.

For 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 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 x 10-6/°C (20 - 40 °C)
    • 11,24 x 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 x 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 x 10-9/K (5 - 35 °C ; 95 % confidence level)
  • Show 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 x °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 materials 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 x cm


Surface Quality


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