If two polymorph any object (PAO) spells are cast in a row with the same end result what happens? PAO is unlike all the other polymorph spells in that your type actually changes. So for the duration what type is used? Your current type from the first PAO spell or the type that you were before PAO was cast?
The duration is based on the target's original state, not it currently transmuted state, as per spell's description:
The duration of the spell depends on how radical a change is made from the original state to its transmuted state.
Keep in mind that the target is not fundamentally a new creature/object, they are still the original target, but with a spell effect on them. So if dispel magic is cast on the target, the effect disapears, even if the duration of the transformation was permanent.
Your creature type is not changed by any of the polymorph spells. A spell that target's animals would not work on you if you are polymorphed into a bear, because your creature type is still humanoid. A rock polymorphed into a tree or dog still cannot be target of the Awaken spell.
Also, the polymorph subschool rules say that you cannot be under the effects of two polymorph at the same time. If that happens, you pick one to take effect:
You can only be affected by one polymorph spell at a time. If a new polymorph spell is cast on you (or you activate a polymorph effect, such as wild shape), you can decide whether or not to allow it to affect you, taking the place of the old spell. In addition, other spells that change your size have no effect on you while you are under the effects of a polymorph spell.