I don't believe there's any way in the current platform to send
notifications to a non-person (triPeople/My Profile) record (I could
be wrong).
If you need to send notifications to an ad hoc address, one option
might be to create a "dummy" person record; then within the workflow
you want to send e-mails from, you can map the e-mail address from
your form onto that person and use it to send the notification.