Blessings on the Torah for Interruptions Between Night Sleeps
Question
Answer
Hello,
If one did not sleep a fixed sleep on the bed, but rather 'dozed off' temporarily, he should not recite the blessing upon awakening, but only after he has slept his full night's sleep.
However, if he slept a fixed sleep and wants to get up for some time and then go back to sleep, he should recite the blessing when he gets up in the middle of the night, and then he does not recite it when he gets up in the morning.
Source
Shulchan Aruch, Orach Chaim, Laws of Morning Blessings and Other Blessings, Siman 47, Seif 13
One who rises before dawn recites the entire order of blessings.
Mishna Berura, Siman 47, SK 30
(30) Before dawn - and even if one rises after midnight for some matter and intends to go back to sleep for a fixed sleep, he can still recite all these blessings and will not need to recite them again when he rises in the morning.