There can be a very large variance in boiling points. It depends on what base stock, what additives, etc... If you check the MSDS for motor oils in question the boiling point is usually listed. Normally they are above 500 degrees F.
Maybe it's volatility your thinking of? Noack Volatility determines the weight lost in the process of operating at the high temperatures. In a comparison graph I can see as high as a 9.5% loss for a common known motor oil brand.
There is no specific site for MSDS's. MSDS stands for material safety data sheet and are published for most every chemical product made. Many lubricant manufacturers list their MSDS's on their website, many don't. You can always call them or drop them a email and they will send you the MSDS for the exact oil in question. No two MSDS's are going to be the same for two different oils.