IRG25 by Schott

Standard Common Environmentally Dangerous

IRG25 by Schott is a standard optical glass with a common melt frequency. It transmits from 1.00 to 15.50 µm. It has high thermal expansion (CTE of 14.0×10⁻⁶/K) and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 1.0–15.5 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 1.0–15.5 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 1.000–15.500 µm
Optical Properties
Refractive Index (nd) —
Abbe Number (Vd) —
Dispersion Formula Sellmeier
Wavelength Range 1.0 — 15.5 µm
$$n(\lambda) = \sqrt{1 + \frac{2.7574\,\lambda^2}{\lambda^2 - 0} + \frac{3.099\,\lambda^2}{\lambda^2 - 0.15961} + \frac{1.666\,\lambda^2}{\lambda^2 - 2045.5}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 14.0
TCE 100/300°C (10-6/K) —
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[5.5 \times 10^{-5} + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{1.21 \times 10^{-5} + 2(0)\,\Delta T}{\lambda - 7.59 \times 10^{-5}}\right] \Delta T = T - T_0, \quad T_0 = 22\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.66
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance —
Stain Resistance —
Acid Resistance —
Alkali Resistance —
Phosphate Resistance —
Notes

Melted frequently and additionally as required

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