In order to define a contextual action for spectrum analysis windows, you need to put your Python script in your Python directory under a directory called Contextual_Spectrum_Analysis_Window.
Go to Tools->Options->Environment->Python Scripts (or Tools->Options->Python->Scripts in INTViewer 5.2) and click "Refresh from Disk". Your script should be listed automatically.
You will now be able to execute this script from the contextual menu of the spectrum analysis window:
This script will cycle the available options for spectrum type and logarithmic factor for the X axis of the window.
This script is attached to the bottom of this article.
The result after the script executes should look something like the following.