If your license expires your account will downgrade to a Limited Free account. Student accounts under your license will also downgrade. Any students in excess of the permitted 10 will be set to inactive. Inactive students can view existing glogs but are not able to edit or create new glogs.
Standard features, such as the ability to view student glogs without a URL, create classes and projects, or add new students (above the maximum of 10) will also be inaccessible. When you renew your license, all of these features will be restored automatically.

Read more about the Limited Free Account.