Low volatility
For reliable performance in high-temperature operating conditions, formulators want base stocks that offer low volatility. In the NOACK volatility test (ASTM D5800), SpectraSyn PAOs demonstrate lower volatility at higher temperatures than Group II and Group III mineral oil base stocks.
High viscosity index
Comparing PAO base stocks at any given viscosity to polyisobutylene (PIB) and mineral oil base stocks, we can see that PAOs provide significantly higher viscosity index (VI). ASTM D2270 is the standard test used for calculating viscosity index from kinematic viscosity at 40° and 100° C. Higher VI translates to better stability in a range of temperatures.