GB/T 42657-2023 in English
VALIDTest method of temperature coefficient of infrared refractive index for infrared optical glass―Normal incidence method
- Issued on:2023-08-06
- Implemented on:2024-03-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$214.00
《GB/T 42657-2023红外光学玻璃红外折射率温度系数测试方法 垂直入射法》由TC447（全国工业玻璃和特种玻璃标准化技术委员会）归口，主管部门为中国建筑材料联合会。
Introduction
1. Standard background and technical evolution
This standard "Test method for infrared refractive index temperature coefficient of infrared optical glass - vertical incidence method" (GB/T 42657-2023) was issued by the State Administration for Market Regulation and the National Administration of Standardization, and is mainly applicable to the test of infrared optical glass with a wavelength of $2\mu\mathrm{m}{\sim}13\mu\mathrm{m}$. The standard is based on the drafting rules of GB/T1.1-2020, proposed by the China Building Materials Federation, and managed by the National Technical Committee for Standardization of Industrial Glass and Special Glass.
This standard fills the gap in the domestic test method for the refractive index temperature coefficient of infrared optical materials, and is of great significance to improving the performance stability of infrared optical devices. Technically, the vertical incidence method is combined with a prism structure to calculate the refractive index and its temperature coefficient by measuring the deflection angle, achieving high precision and efficiency.
2. Comparison of standard frameworks
| Standard dimensions | Range requirements | Technical requirements | Test methods |
|---|---|---|---|
| Applicable waveband | $2\mu\mathrm{m}{\sim}13\mu\mathrm{m}$ | Infrared optical glass and other materials | Vertical incidence method, prism structure |
| Temperature control | $-60^\circ\mathrm{C}{\sim}160^\circ\mathrm{C}$ | Temperature control accuracy ±0.2°C, vacuum environment requirements | Liquid nitrogen refrigeration and heating system coordination |
| Measurement accuracy | Deflection angle measurement error ≤0.5'' | High refractive index calculation accuracy | d>Data processing and statistical analysis methods
Table 1: Comparison of infrared optical glass test standard framework (based on GB/T 42657-2023)
3. Recommendations for standard implementation
3.1 Test equipment selection and calibration
- Select an infrared light source and monochromator that meet the requirements to ensure that the wavelength covers the full range and the resolution is better than 5nm;
- Precision goniometers need to be calibrated regularly to ensure that the angle measurement accuracy is ≤0.5'';
- The temperature control system should meet the requirements for stable control in a vacuum environment. It is recommended to use a dual-channel sensor for real-time monitoring.
3.2 Sample preparation and processing
- The sample must meet the requirements for impurity and streak levels in GB/T 36265-2018;
- Pretreatment should be performed in a standard environment for at least 24 hours before testing to ensure temperature stability;
- The sample surface should be polished to Ra≤0.012 and the surface accuracy should be ≤λ/10 (λ=632.8nm).
3.3 Data Processing and Result Analysis
- The test data should record the temperature, wavelength and deflection angle, and calculate the refractive index and temperature coefficient;
- It is recommended to use the least squares fitting method to determine the optimal temperature change range and its corresponding relationship;
- The report must include complete experimental conditions and error analysis.
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