Not each use of quartz glass need to anneal. The annealing method solves the problems of annealing efficiency and high cost of large-size quartz glass. This not only ensures quartz glass to remove stress birefringence and no deformation, but also can make efficient annealing and improve production efficiency.
Anealing Processing:
First, place quartz glass in the annealing furnace.
Then, the chamber temperature of the annealing furnace is raised to 1090-1200 ℃ by the rising rate of 200-250 ℃ per hour and kept for 6-8 hours.
The next step is to down the temperature of the annealing furnace to 1035-1050 ℃ with a cooling rate of 3-5 ℃ per hour, and keep the temperature for 6-8 hours.
Further step, down the temperature of the annealing furnace to 900 ℃ with a cooling rate of 15-20 ℃ per hour.
Finally, after cooling to 200 ℃, open the furnace door, place quartz glass in the air and wait for it to be in normal temperature.
The main reason for annealing quartz glass is to meet the following two characteristics.
First, quartz glass is annealed in order to make its overall stress equilibrium. The advantage is that after heating it to a high enough temperature, it will cool down quickly without cracking. This feature can meet all the production requirements in the current industry.
Second, high temperature annealing can also reduce the water molecular content inside quartz glass called OH. The decrease of Oh will also make quartz glass perform in the best state. For instance, quartz glass as a bubble shell get the best performance in strong light source.
