First, polymer clay never *needs* any sealing at all like air-dry clays do. Polymer clay is a plastic, so it's oil-based and waterproof already (whether raw or cured).

Generally, coats of clear gloss liquid or color acrylic paints are put onto clay (if they're even used) *after* the clay is already cured, but some can be used before without problems or even "re-baked" on purpose.

The main problem you may be running across though is that because polymer clay is a plastic, it can be eaten into by some solvents (those that are petroleum-based, and must be thinned or cleaned up with paint thinner, etc., instead of water). The eating-into/dissolving of the clay can begin happening right away leaving a sticky feel, or it can suddenly happen up to 6 months later. Some sprays can be a problem too since even acrylic paints can have the "bad" solvent only in the propellants of their sprays.
(This kind of thing also happens if raw polymer clay is left in direct contact with certain other kinds of plastics --many kinds of clear hard plastics, though not all...over time the oily plasticizer in the clay will begin dissolving the hard plastic leaving a gooey area.)

So I think that you may have used a "clear paint" (not really a "paint" though since paints have color) that shouldn't be used directly on polymer clay.
I'm not familiar with "Glaze Sparkle" so can't say exactly what it's made from. But if you want to use it again sometime, first coat the plain baked clay with acrylic paint or with a water-based acrylic sealer and let dry, THEN add the Glaze Sparkle.
(There are other ways to get "sparkliness" onto polymer clay though, sometimes as "inclusions" of microfine glitter added into clear liquid finishes that are safe for polymer clay, sometimes in other ways.)

If you used a really thick coat, or several coats that weren't allowed to dry *thoroughly* in between, you could just have a drying problem too but usually several days should be enough even if that were true.

Sometimes finishes like that can be "re-baked" to harden them or harden them further, but if you don't want to do that you could always apply a "safe" clear finish on top of the other stuff and that would probably work.

You can read a lot more about all those things on these pages of my polymer clay "encyclopedia" site, if you're interested:

http://glassattic.com/polymer/finishes.htm
http://glassattic.com/polymer/baking.htm
http://glassattic.com/polymer/powders_metallicwaxes.htm (especially the category *As Paints*)
http://glassattic.com/polymer/paints.htm

HTH,
Diane B.