SCHOTT N-BK7® Optical Glass

Glass Type: Optical Glass


SCHOTT N-BK7® is an optical glass with high transmission and is virtually free of bubbles and inclusions. SGP can CNC mill, drill, cut, lap, and polish this material to many shapes, sizes, and surface finishes.

Thermal PropertiesMechanical Properties
Thermal Coefficient of Expansion(0/300°C): 70 X 10 -7/°CDensity2.51 g/cm3
Annealing Point550°C/1022 °FKnoop Hardness610
Softening Point719°C /1326 °FYoung's Modulus8.20 X109 dynes/mm2
Strain Point624°C/1155 °FPoisson's Ratio.206
Chemical PropertiesElectrical Properties
Hydrolytic Resistanceclass 2Dielectric ConstantN/A
Acid Resistanceclass 1ResistivityN/A
Alkali Resistanceclass 1Dielectric StrengthN/A
Optical Properties
Refractive Index1.509