Based on my understanding of how loaded/unloaded chunks work, I wanna say the answer is yes. Even if it takes you hours to get back to the spot you died, the fact that you were far away enough for the chunk to unload means the timer will be frozen.
Of course, once you are close enough to your corpse that the chunk DOES load, then I imagine the despawn-timer picks right back up wherever it left off.
At least, I'm pretty sure this is the case.