P-BK7 by Schott

Preferred Unknown Precision Molding Environmentally Friendly

P-BK7 by Schott is a preferred optical glass. It transmits from 0.31 to 2.50 µm with an nd of 1.5164 and a Vd of 64.06. It has low thermal expansion (CTE of 5.99×10⁻⁶/K), good chemical resistance, and precision molding compatibility.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.31–2.5 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.31–2.5 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.310–2.500 µm
Optical Properties
Refractive Index (nd) 1.5164
Abbe Number (Vd) 64.06
Dispersion Formula Sellmeier
Wavelength Range 0.31 — 2.5 µm
$$n(\lambda) = \sqrt{1 + \frac{1.18319\,\lambda^2}{\lambda^2 - 0.00722142} + \frac{0.0871756\,\lambda^2}{\lambda^2 - 0.0268217} + \frac{1.03134\,\lambda^2}{\lambda^2 - 101.702}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 5.99
TCE 100/300°C (10-6/K) 7.32
Thermal Conductivity (W/mK) 1.13
Heat Capacity (J/gK) 0.87
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[5.96 \times 10^{-6} + 2(1.36 \times 10^{-8})\,\Delta T + 3(1.04 \times 10^{-12})\,\Delta T^2 + \frac{5 \times 10^{-7} + 2(6.97 \times 10^{-10})\,\Delta T}{\lambda - 0.125}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 2.433
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) 84.78
Poisson's Ratio 0.2
Knoop Hardness (kgf/mm²) 627.0
Chemical Resistance
Climatic Resistance 1
Stain Resistance 0
Acid Resistance 1
Alkali Resistance 2
Phosphate Resistance 2
Notes

suitable for precision molding

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Glass Manufacturer nd Vd Compare
D-K9 CDGM 1.51633 64.058952
D-K9GT CDGM 1.51633 64.058952
L-BSL7 Ohara 1.51633 64.065129
BK7 Sumita 1.51633 64.1
K-BK7 Sumita 1.51633 64.1
S-BSL7 Ohara 1.51633 64.142022
BSL7 Ohara 1.51633 64.150145
D-K9-25 CDGM 1.51577 63.989637
D-K9GT-25 CDGM 1.51577 63.989637
H-K9LAGT CDGM 1.5168 64.198695
Similar Glasses (Schott)
Glass Manufacturer nd Vd Compare
BK7HT Schott 1.51633 64.14348
BK7 Schott 1.5168 64.167336
N-BK7 Schott 1.5168 64.17
N-BK7HT Schott 1.5168 64.17
N-BK7HTSultra Schott 1.5168 64.17
N-BK7HTi Schott 1.5168 64.17
UBK7 Schott 1.516801 64.289727
BK8 Schott 1.520152 63.685744
BK7G18 Schott 1.51975 63.58
PK2 Schott 1.518211 65.054286
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