If you would like to make a form available only during a certain time of day you can use the following Reference ID 1:
1) Go in to the form and select the Edit button.
2) Enter PAGETYPE_TIMEAWARE=9:00-19:00 in the Reference ID 1 field.
Using this Reference ID will only allow the form to be available from 9 AM until 7 PM. You can adjust the time as you see fit.