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Optical Glass (N-BK7 B270 and others) |
| N-BK7 is a Schott designation for the most common Borosilicate Crown glass used for a wide variety of visible applications. The basic data here is given for N-BK7. Full optical design data on N-BK7 and other glasses can be found by following the web links at the bottom of this page. |
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Product Data |
| Transmission Range : |
350nm to 2.5 μm |
| Refractive Index : |
1.51680 @ 587.5618 nm (Yellow Helium Line) |
| Reflection Loss : |
8.1% at 587.5618 nm (2 surfaces) |
| Absorption Coefficient : |
-- |
| Reststrahlen Peak : |
-- |
| dn/dT : |
See Schott Table |
| dn/dμ = 0 : |
-- |
| Density : |
2.51 |
| Melting Point : |
557°C (Transformation Temperature) |
| Thermal Conductivity : |
1.114 W m-1 K-1 |
| Thermal Expansion : |
7.1 x 10-6 K-1 |
| Hardness : |
Knoop 610 |
| Specific Heat Capacity : |
858 J Kg-1 K-1 |
| Dielectric Constant : |
n/a |
| Youngs Modulus (E) : |
82 GPa |
| Shear Modulus (G) : |
n/a |
| Bulk Modulus (K) : |
34 GPa |
| Elastic Coefficients : |
n/a |
| Apparent Elastic Limit : |
63.5MPa (9206psi) |
| Poisson Ratio : |
0.206 |
| Solubility : |
Insoluble in water |
| Molecular Weight : |
n/a |
| Class/Structure : |
Amorphous glass |
To download this data or our MSDS safety data sheet as a pdf, please click on the links at the top of the page. To expand the transmission graphs, please click on the image.
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Product Notes |
These two optical glasses are selected as representative of typical Crown Glass formulations in common use. There are many other glasses including higher density and higher dispersion glasses. Link below to access a larger range.
WEBLINKS:
Schott Glass Catalogue - Data on all Schott Glass types.
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Data provided is extracted from our technical handbook of materials. While every attempt has been made to verify the source of the information, Crystran Ltd accept no responsibility for accuracy of data |
