The default time period for a SSO session is 10 hours in the Identity Server versions so far and this default SSO Session Expire time value cannot be changed according to the user's needs. However, from WSO2 IS 4.5.0 onwards, the SSO session timeout can be configured at the server start time.
This configuration can be found in the <IS_HOME>/repository/conf/identity.xml file under the SSOService element. Add the following entry under this element in order to explicitly add the SSO timeout:
<SSOService> <SessionTimeout>120</SessionTimeout> // Add the expecting timeout value in seconds here. </SSOService>
Save the configuration modifications and restart the server. Now the SSO session is timed out as the newly configured value and users may need to be re-authenticated once the session times out. It is not a must to have this entry in 'identity.xml' and if a timeout is not configured, the SSO session uses the '10 hours (36000s)' default time out value.
After configuring the SSO Session Expire Time you can see here in order to setup Single Sign On with WSO2 Identity Server.