A free app for Chrome, by CloudCodes Software Pvt. Ltd..
This is an extension to CloudCodes for G Suite, which provides an extra set of controls for Google Apps. This allows administrators to control access to their employees’ Gmail accounts, block access to the personal Gmail accounts of any employee, and enable or disable access to all Gmail accounts in the organization.
You will need to install the CloudCodes for G Suite application in order to use this extension.
You need to enable the settings in the application in order to block access to your personal Gmail account.
You can install the CloudCodes for G Suite extension for Chrome and use it in the same way as the gControl extension.