There's a LOT of valuable information about Glycerin/Glycerine and other 'sugar alcohols' right here on this site.

A Search of this Forum gets you a ton of valuable discussion (use 'glycerin' as the search keyword).

And there's a fabulous article written by our own Doreen T, SuperWoman over there for quick access on the right side of your screen: The truth about low carb sweeteners info, including the sugar alcohols and all kinds of sweeteners, both the AS(s) and the Bulk Sweeteners!

Well worth the time.