SF18 by Schott

Obsolete Unknown Environmentally Dangerous

SF18 by Schott is an obsolete optical glass. It transmits from 0.35 to 2.33 µm with an nd of 1.72151 and a Vd of 29.245495. It has medium thermal expansion (CTE of 8.1×10⁻⁶/K), average chemical resistance, low relative cost, and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.334–2.325 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.334–2.325 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.350–2.325 µm
Optical Properties
Refractive Index (nd) 1.72151
Abbe Number (Vd) 29.245495
Dispersion Formula Sellmeier
Wavelength Range 0.334 — 2.325 µm
$$n(\lambda) = \sqrt{1 + \frac{1.56441\,\lambda^2}{\lambda^2 - 0.0121864} + \frac{0.291414\,\lambda^2}{\lambda^2 - 0.0535568} + \frac{0.960308\,\lambda^2}{\lambda^2 - 111.451}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 8.1
TCE 100/300°C (10-6/K) 9.0
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[4.66 \times 10^{-6} + 2(1.71 \times 10^{-8})\,\Delta T + 3(-4.9 \times 10^{-11})\,\Delta T^2 + \frac{1.41 \times 10^{-6} + 2(1.31 \times 10^{-9})\,\Delta T}{\lambda - 0.26}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.49
Relative Cost 2.25
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 2
Stain Resistance 1
Acid Resistance 3
Alkali Resistance 2
Phosphate Resistance 3
Notes

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Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
FD18 Hoya 1.721507 29.243436
PBH18 Ohara 1.721506 29.243262
S-TIH18 Ohara 1.721507 29.23233
SF18 Sumita 1.72151 29.3
CD120 Sumita 1.7225 29.2
K-CD120 Sumita 1.7225 29.2
FD20 Hoya 1.720225 29.300359
SFN1 Sumita 1.72022 29.3
D17-29 Corning 1.717409 29.492751
H-ZF3 CDGM 1.71736 29.49911
Similar Glasses (Schott)
Glass Manufacturer nd Vd Compare
P-SF69 Schott 1.7225 29.23
SF1 Schott 1.71736 29.51
N-SF1 Schott 1.71736 29.62
SF53 Schott 1.728301 28.68667
N-SF10 Schott 1.72828 28.53
SF10 Schott 1.72825 28.41
N-SF64 Schott 1.70591 30.23
SF64A Schott 1.70585 30.299703
SF3 Schott 1.74 28.2
SF54 Schott 1.7408 28.090813
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