PBM27 by Ohara

Obsolete Unknown Environmentally Dangerous

PBM27 by Ohara is an obsolete optical glass. It transmits from 0.33 to 0.90 µm with an nd of 1.639799 and a Vd of 34.477127. It has medium thermal expansion (CTE of 8.8×10⁻⁶/K), good chemical resistance, and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.3–2.4 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.3–2.4 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.330–0.900 µm
Optical Properties
Refractive Index (nd) 1.639799
Abbe Number (Vd) 34.477127
Dispersion Formula Schott
Wavelength Range 0.3 — 2.4 µm
$$n(\lambda) = \sqrt{2.61241 - 0.00873166\,\lambda^2 + 0.0248578\,\lambda^{-2} + 0.000887786\,\lambda^{-4} - 9.26403 \times 10^{-6}\,\lambda^{-6} + 4.50287 \times 10^{-6}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 8.8
TCE 100/300°C (10-6/K) 9.8
Thermal Conductivity (W/mK)
Heat Capacity (J/gK)
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[5.245 \times 10^{-6} + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 25\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.78
Relative Cost
Mechanical Properties
Young's Modulus (GPa)
Poisson's Ratio
Knoop Hardness (kgf/mm²)
Chemical Resistance
Climatic Resistance
Stain Resistance
Acid Resistance 1
Alkali Resistance
Phosphate Resistance 2
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
H-F51 CDGM 1.6398 34.46457
FD7 Hoya 1.639803 34.568909
E-FD7 Hoya 1.6398 34.57
SF7 Sumita 1.6398 34.6
C37-35 Corning 1.636493 35.322642
SF16 Schott 1.646112 34.049815
F6 Hoya 1.636356 35.340304
F6 Schott 1.636359 35.341176
F7 CDGM 1.636365 35.386204
F6 Sumita 1.63636 35.4
Similar Glasses (Ohara)
Glass Manufacturer nd Vd Compare
S-TIM27 Ohara 1.639799 34.466422
PBM6 Ohara 1.636358 35.376536
S-TIM6 Ohara 1.636358 35.391923
PBM22 Ohara 1.647689 33.802937
S-TIM22 Ohara 1.647689 33.792803
S-TIM1 Ohara 1.625882 35.699614
PBM1 Ohara 1.625882 35.700668
PBM11 Ohara 1.620955 35.880852
TIM11 Ohara 1.620955 35.880852
PBM2 Ohara 1.620041 36.256658
Compare Glasses