The ng-src AngularJS directive is used to bind an iframe source Url to a scope property. During performance testing, I noticed in IE (10 and 11), that the Url was being updated twice. This causes two GET requests, which slowed the page load down.
Office 365’s single sign-on capabilities with ADFS are a great improvement over dual-identities, and it takes online users a step closer to the seamless experience they have become accustomed to with an on premise web application. If you’re looking to set it up, Microsoft provide some great information and even some step-by-step videos: https://support.microsoft.com/en-us/kb/3061192.