How long a notarized power of attorney lasts depends on the terms of the agreement.
For example, a nondurable power of attorney generally lasts up to the point the principal loses capacity. A durable power of attorney, on the other hand, generally lasts for the principal’s lifetime, so long as it is not revoked before the principal dies.
Put simply, a power of attorney being notarized does not make it last longer. All POAs end at death.