Technically speaking it is possible, but personally, I would not risk it with two blank pages, considering:
- At departure from India, you'll get an exit stamp.
- At arrival in Turkey, you will get an entry stamp.
- At departure from Turkey, you will get an exit stamp.
- At arrival in Romania, you'll receive an entry stamp (Romania is not part of Schengen).
- At departure from Romania, you'll recieve an exit stamp.
- At arrival in the Schengen area (Spain), you'll receive an entry stamp.
- Travel between Spain and Austria (and in the Schengen zone) is stamp-free.
Assuming you intend to go back to India, you'll have to have room for the various exit stamps you'll need. At least one for exit from the Schengen zone, and then one for entry into India.
From my travels through Schengen they always stamp the exit next to the entry stamp, and they have never stamped on a non-blank page.