The cooling rate has a great influence on the performance of chalcogenide glass, but it is unclear how much the actual cooling rate changes with different cooling methods. In this study, the infrared thermal imaging technology was employed to observe the temperature change in various cooling methods. The temperature curves and the cooling rates between different cooling methods were analyzed from the infrared images. The results show that at 250 °C, the cooling rates follow the order: water quenching > air compressor cooling > salt bath cooling > air cooling > asbestos wrapping cooling; whereas at 150 °C, the sequence is: water quenching > air compressor cooling > air cooling > asbestos wrapping cooling > salt bath cooling. Then the temperature changes inside the sample was simulated and the result shows that the temperature gradient of water quenching is much greater than that of air cooling method, which is why cracks often appear in the glass prepared by water quenching. Finally, Gex-S(90-x)-Sb10 glass was successfully prepared using the air cooling method and it shows excellent optical properties that can transmit both visible and infrared light. © 2023 Elsevier B.V.