I assumed that they were freezer safe because on the packaging it says that you can put them in the freezer. Many of the icicles toys here at Edens have that in their description.
One example is the Icicles 28
Under product details it states "Run the wand under warm water or place it in the microwave to heat things up. Chill it under cold water or put it in the freezer for a cool sensation."
I don't know if this applies to all glass toys though and I know I didn't specifically mention the Icicles brand in my original question.
Any more info is much appreciated cause I never even thought it was a dangerous thing to do.