LaSFN9

BK7, SF11, LaSFN9, BaK1, and F2 are the most important optical and physical constants for Schott optical glass types. These types are used in most Dream Lasers simple lens products and prisms. The most commonly required chemical characteristics and mechanical constants, are listed. Further numerical data and a more detailed discussion of the various testing processes can be found in the Schott Optical Glass catalog.

LaSFN9 Constants
Abbé Constant
32.17
Density
4.44 g/cm-3
Young's Modulus
1.09 x 109 dynem2
Poisson's Ratio
0.286
Coefficient of Thermal Expansion (-30° to +70°C)
7.4 x 10-6/°C
Coefficient of Thermal Expansion (20° to 3000°C)
8.4 x 10-6/°C
Stress Birefringence, (Yellow Light)
10 nm/cm
Melt-to-Melt Mean Index Tolerance
±0.002
Homogeneity within Melt
±1x10-4
Striae Grade (MIL-G-174-A)
A
Transformation Temperature
703°C
Climate Resistance
2
Stain Resistance
0
Acid Resistance
2.0
Alkali Resistance
1.0
Phosphate Resistance
1.0
Knoop Hardness
630
Dispersion Constants
B1 = 1.97888194 
B2 = 3.20435298x10-1 
B3 = 1.92900751
C1 = 1.18537266x10-2 
C2 =5.27381770x10-2 
C3 = 1.66256540x102
The external transmittance of LaSFN9 is shown in the figure below:
External transmission for 10-mm-thick LaSFN9 glass