Borosilicate Glass vs. Potassium Bromide
Borosilicate glass belongs to the glass and glass-ceramics classification, while potassium bromide belongs to the non-glass optical ceramics. There are 14 material properties with values for both materials. Properties with values for just one material (15, in this case) are not shown.
For each property being compared, the top bar is borosilicate glass and the bottom bar is potassium bromide.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 67 to 80 | |
| 24 |
| Poisson's Ratio | 0.21 | |
| 0.17 |
Thermal Properties
| Melting Onset (Solidus), °C | 560 | |
| 730 |
| Specific Heat Capacity, J/kg-K | 830 | |
| 450 |
| Thermal Conductivity, W/m-K | 1.2 | |
| 4.8 |
| Thermal Expansion, µm/m-K | 3.3 to 5.1 | |
| 39 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 5.4 | |
| 4.9 |
| Electrical Dissipation At 1 MHz | 0.0017 to 0.0088 | |
| 0.00020 |
Otherwise Unclassified Properties
| Density, g/cm3 | 2.2 to 2.6 | |
| 2.8 |
| Light Transmission Range, µm | 0.3 to 2.5 | |
| 0.22 to 26 |
| Refractive Index | 1.5 | |
| 1.8 |
Common Calculations
| Stiffness to Weight: Axial, points | 15 to 17 | |
| 4.7 |
| Stiffness to Weight: Bending, points | 55 to 61 | |
| 35 |
| Thermal Diffusivity, mm2/s | 0.54 to 0.63 | |
| 3.9 |