What is the relation between Nirvana and Parinirvana? The Buddha attained Nirvana at the age of 35. He lived 45 years more after which his Parinirvana occurred. Is it not somewhat contradictory? If Nirvana means the end of rebirth and rebirth means the evolution of consciousness, did the Buddha possess no consciousness during the last 45 years of his life?
What the Buddha experienced at 35 was called sa-upādisesa-nibbāna - nirvana with remainder. What he experienced at 80 was called anupādisesa-nibbāna - nirvana without remainder:

“dvemā, bhikkhave, nibbānadhātuyo. katame dve? saupādisesā ca nibbānadhātu, anupādisesā ca nibbānadhātu.
There are these two, monks, elements of nibbāna. What two? The element of nibbāna with remainder and the element of nibbāna without remainder.
-- Iti. 44

The difference is that after the former, there is still sequences of physical and mental formations that continue as a consequence of the birth of the being and have to work themselves out, which they do at the latter, signifying an end to all such physical and mental formations.
The actual experience of nirvana during the former (which can last from a few moments up to seven days) and the latter (which, due to there being no remaining sequence of formations and no craving to create new ones, is permanent) is the same.