In Service Manager 9.52, it does not appear that Time Period Management is sending out any Email notifications to the owner, owning group or the delegates associated with the Time Period record. There are no emails sent after the record is created or is in Pending Approval state. The only place that email is sent to Owner and Owning Group is after the approval.
Steps to reproduce:
1. Create new Time Period Definition and save it. (Make sure to fill in Owner and Owning Group fields).
2. Approve the record.
3. Retire the record.
4. Observe eventout and only emails that you will see are After Approval emails to Owner and Owning Group.