| Typical
Composition |
Physical
Properties |
| SiO2
...............72.0% |
Working
point ...........11500C |
| B2O3
................9.0% |
Softening
point ..........7650C |
| Al2O3
................5.1% |
Annealing
point ..........5500C |
| Na2O
................7.6% |
Strain
point ...............5200C |
| K2O
..................1.9% |
Coefficient
of expansion |
| CaO
..................1.1% |
(300C-3000C)
.............57x10-7 |
| BaO
..................3.0% |
Density
..................2.43g/cc |