Android devices running Android version 4.2 (Jellybean) and above have the following process for logging into a captive portal protected Wi-Fi network:
1. User connects Android device to the Open Wi-Fi network which uses captive portal based authentication. Android displays a notification on screen for signing into the Wi-Fi with credentials.
2. Clicking on the Notification pop-up brings up a browser window with the captive portal page prompting for the credentials.
3. Entering the credentials and clicking on "Log In" automatically closes the browser on successful login.
If any page has to be displayed post-authentication such as a Self-service portal, this would not be possible. The only way to display the post authentication pages would be to ask users to dismiss the "Sign into Wi-Fi network" notification and open a browser manually by launching it from the application list.
4. This will then enable displaying of post-authentication pages as shown below.