Phenyl silicone oil, as an important branch of organic silicon materials, exhibits outstanding thermal stability due to its unique molecular structure design. Compared to ordinary dimethyl silicone oil, the introduction of the phenyl group significantly alters the flexibility and chemical stability of the molecular chain, enabling it to demonstrate superior performance in high-temperature environments. 
From a molecular perspective, the aromatic ring structure of the phenyl group endows the molecular chain with greater rigidity, effectively inhibiting molecular chain breakage and rearrangement reactions under high temperatures. Experimental data show that phenyl silicone oil with a low phenyl content (5%-10%) can be used for a long time at 200°C, while products with a high phenyl content (above 25%) can have a thermal decomposition temperature of over 350°C, and even withstand a 400°C temperature shock within a short period of time, far outperforming traditional mineral oils and ordinary silicone oils. 
The thermal stability of phenyl silicone oil is also reflected in its performance retention rate under high temperatures. Under continuous high-temperature conditions, the viscosity change rate is typically less than 15%, and no obvious oxidation discoloration or carbonization occurs. By introducing methyl phenyl silicone oxygenane linkages or adding antioxidants, the thermal oxygen stability can be further improved to meet more stringent working conditions. 
This excellent thermal stability makes it widely used in high-temperature lubricants, heat transfer oils, and electronic packaging materials, etc. For example, in the lubrication system of automotive engines, phenyl silicone oil can effectively resist high-temperature oxidation degradation; in the LED packaging field, it can maintain its thermal conductivity and insulation performance for a long time, providing reliable protection for electronic components.