Retrieving time stamp without date

Does anyone know of a way to pull a time stamp ONLY, without including the date? I can't seem to find a suitable method here: https://wiki.servicenow.com/index.php?title=GlideDateTime

The use case is defining a relative SLA duration of "1 business day", so the SLA target should be the next business day at the time when the SLA clock started. I'd welcome any thoughts around an alternative solution to this, of course.

Thanks!