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Optical Glass (N-BK7 and others)

♦ Optical Glass (N-BK7 types) Data Sheet    ♦ Optical Glass (N-BK7 types) MSDS

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. There is a huge range of glasses available for which we hold data and some stock.

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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