And to add to this, TGA is a method for determining mass loss, from which one can infer Noack:
To decide if TGA is appropriate for your polymer material testing goals, it is helpful to understand how thermogravimetric analysis works.
www.ace-laboratories.com
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TGA provides quantitative measurement of mass change in materials associated with transition and thermal degradation. TGA records change in mass from dehydration, decomposition, and oxidation of a sample with time and temperature.
vs Noack:
en.wikipedia.org
"In this test, a sample is heated at 250 °C for 60 minutes with a constant flow of air over it. The weight fraction lost is the result for the Noack volatility test."
So, if you run TGA at 250 on an oil with a known Noack of 8% then on another product and it loses less mass, you can infer that Noack of the other product is 8% or lower.