Dear Justin,

you can try checking "Logs"->"System Events"->"Notifications", but please bear in mind that entries there are purged after 30 days (30 is the default setting, the actual setting in your setup might even be shorter), and that through summarization a relation between trigger/notification and sent email might not be exactly possible.

best regards.

You can setup the notification to also execute a batch file that does the logging for you.

See KB topic: http://kb.paessler.com/knowledgebase/en/topic/20553-report-of-all-alerts-received