This tutorial shows the process of importing email from Office 365 Exchange to Gmail.
You will see the following message:
Your messages are being imported. It may take several hours (sometimes up to 2 days) before you start to see imported messages. You can close this window and keep using University of Colorado Boulder Mail or even log out and close your browser – we'll continue importing your mail and/or contacts in the background. To check the status of your import, look under Settings > Accounts and Import
In the Account and Import section the import status will be displayed under Check mail from other accounts: