I do not remember as to why she is cryogenized in the first place, but the device is pretty resilient and supports her waking in different periods of Earth evolution, when, by various events, she is forced to reenter the device to escape danger, and sleep until the next period. I think the last awakening is some million years in the future, when she witnesses a cataclysmic event (the Sun dying perhaps?). For a while I thought is one of Asimov's novels, but after searching high and low, I'm not so sure anymore.
It wasn't specifically freezing, more like suspended animation by some substances with tubes connecting to the veins.
I'm not so sure when I read it, perhaps like 15-20 years ago. But it wasn't a new novel even then.