China Glaze Questions

Could somebody who uses the China Glaze polishes tell me whether they
are toluene and formaldehyde free?
Has anyone used any of their treatments? base coat, top coat etc.
There's a bunch here.
http://www.transdesign.com/Treatments/China%20Glaze%20Treatments.htm
BTW, does anyone know why some topcoats require UV light to cure?
Thanks, Abby