GFK68 by Sumita

Obsolete Very Rare Environmentally Dangerous

GFK68 by Sumita is an obsolete optical glass with a very rare melt frequency. It transmits from 0.28 to 2.00 µm with an nd of 1.5924 and a Vd of 68.3. It has excellent chemical resistance and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.27–2.0 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.27–2.0 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.280–2.000 µm
Optical Properties
Refractive Index (nd) 1.5924
Abbe Number (Vd) 68.3
Dispersion Formula Schott
Wavelength Range 0.27 — 2.0 µm
$$n(\lambda) = \sqrt{2.49983 - 0.00611895\,\lambda^2 + 0.0125135\,\lambda^{-2} + 0.00022375\,\lambda^{-4} - 5.43494 \times 10^{-6}\,\lambda^{-6} + 2.97403 \times 10^{-7}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) —
TCE 100/300°C (10-6/K) 15.2
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.51
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance 1
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
D-ZPK5-25 CDGM 1.59216 68.281511
D-ZPK5 CDGM 1.5928 68.342024
H-ZPK5 CDGM 1.5928 68.342024
N-PSK57 Schott 1.5924 68.398667
FCD505 Hoya 1.59282 68.62
FCD515 Hoya 1.59282 68.62
S-FPM2 Ohara 1.59522 67.735723
H-ZPK3 CDGM 1.59349 67.285372
D-ZPK3 CDGM 1.59419 67.295385
B96-67 Corning 1.596306 67.398269
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
K-GFK68 Sumita 1.5924 68.3
K-GFK68(M) Sumita 1.58998 68.3
K-PSK400(M) Sumita 1.59179 67.7
K-PSK400 Sumita 1.595 67.8
K-PSK300 Sumita 1.5995 65.6
K-PSK300(M) Sumita 1.5969 65.3
GFK70 Sumita 1.56907 71.3
K-GFK70 Sumita 1.56907 71.3
K-PMK155 Sumita 1.5582 68.2
K-GFK70(M) Sumita 1.56627 71.3
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