Test method for thermochromism of quartz glass
1. Test principle: after heat treatment, the light transmittance of transparent quartz glass changes. The change of transmissivity at 290n m wavelength is used as a measure of the color change performance.
2 sample preparation
2.1 quantity: three.
2.2 the shape and size shall be in accordance with the following table: mm
Style, shape and size of pipe or product
The pipe with diameter less than 40 shall be 30-40 long and cut into two parts axially
The tube with diameter greater than 40 is 30-40 in length and cut into the pattern with chord width of 20
Product 30 × 15 × s (plate thickness)
2.3 the appearance quality of the sample shall conform to the corresponding JC 177-81 dtsi transparent quartz glass tube or JC 224-81 dts2 transparent quartz glass tube.
3 test equipment and materials
3.1 one high temperature electric furnace with working temperature of 1000 ± 20 ℃.
3.2 one electric oven.
3.3 one UV spectrophotometer, the measurement accuracy of transmittance is ± 1%.
3.4 quartz glass sample box with cover, specification and size of Φ 100mm x 80mm.
3.5 one chrome plated crucible clamp and one bamboo clamp respectively.
3.6 one 125mm vernier caliper with an accuracy of 0.02mm.
3.7 chemical pure anhydrous ethanol.
3.8 absorbent gauze or absorbent cotton.
3.9 glass beaker.
4 test preparation
4.1 sample preparation
4.1.1 immerse the sample in a beaker with anhydrous ethanol for 15-20min, take it out and wipe it with absorbent gauze.
4.1.2 treat the sample box and cover for the test with the same method.
4.1.8 place the sample in the sample box with the clamp, place the sample box and the cover containing the sample in the oven, and dry (the cover is not covered when drying) for use.
4.2 temperature rise: raise the furnace temperature to 1000 ± 20 ℃.
4.3 adjust the UV spectrophotometer.
5 test steps
5.1 adjust the wavelength dial of the spectrophotometer to 290 nm and calibrate 100% transmittance.
5.2 put the processed sample into the sample holder of the UV spectrophotometer, and record the transmittance curve from 200 nm to 400 nm.
5.8 put the tested sample into the sample box, cover it, and put it into the high-temperature electric furnace prepared according to 4.2 for 2 hours.
5.4 take out the sample box containing the sample from the furnace, cool it in the air, and measure the transmittance of the sample according to 5.2.
6 calculation of results
6.1 discoloration property of quartz glass after heat treatment, expressed as △ T,% / mm at the wavelength of 290 nm for the sample with unit thickness, and calculated as follows: △ t = (T1-T2) / D, where: T1 is the transmittance at 290 nm before heat treatment of the sample, T2 is the transmittance at 290 nm after heat treatment of the sample, D is the thickness of the sample, mm. 6.2 take the average value of the change value of the transmittance of three samples as the change value of the transmittance of this batch of samples.
7 test record and test report
7.1 record the sample number and sending unit on the recording paper of spectral transmission curve.
7.2 test report: fill in the test report.