To set the Notification duration:
Ensure that Notify is running.
Right-click on the Windows taskbar, and then click Options.
Click the Notify tab.
Ensure that Show dialog is selected for the item types and priorities you want.
Click the General tab.
Type the number of seconds you want the dialog box to display under Show Notify dialog for.
You can specify up to 32,767 seconds, which is just over nine hours.
Click OK.