In many cases, Articles, VideoObjects, etc are about a particular moment within an Event. Currently, there is no way to specify the time of the moment being discussed.

We should add a new property contentReferenceTime to CreativeWork to for this purpose. The property would expect the wall clock datetime of the moment as calculating the time elapsed within an event can be difficult. As an example:

{
  "@context": "http://schema.org/",
  "@type": "Article",
  "name": "Apple announces iPhone SE",
  "description": "New iPhone announced at 11:30 in California.",
  "about": {
    "@type": "Event",
    "name": "Apple's March 21 Announcements"
  },
  "contentReferenceTime": "2016-03-21T11:30:00-07:00"
}