The disappearance of one form and the appearance of another is generally the simple definition of Pariṇāma (परिणामे तु रूपान्तरं तिरोभवति, रूपान्तरं च प्रादुर्भवतीत्युक्तम्). The classic example is the case of milk and curd. On the other hand, Vivartavāda is illustrated through popular examples such as marīcyambhaḥ (mirage water), rajju-sarpa (appearance of the rope as a snake), śukti-rajata, etc. Several great scholars of yore such as Bhartr̥hari, Bhavabhūti, śāntarakṣita, and others have used the two terms pariṇāma and vivarta interchangeably:
शब्दस्य परिणामोऽयमित्याम्नायविदो विदुः |
छन्दोभ्य एव प्रथममेतद्विश्वं व्यवर्तत ||
In his magnum opus Saubhāgyabhāskara, Bhāskararāya Makhīndra asserts thus: like the clay and its pariṇāma, the pot, according to the adherents of Tantra śāstra, there no bhēda (in essence) between brahma and the jagat. Thus, satyatva is not only applicable to brahman but to jagat also. The real falsehood here is only of the bheda and by accepting this, there is an automatic accomplishment of all Advaita-para statements of śruti. Further, when dealing with chāndōgya shruti वाचारम्भणं विकारः, and the sūtra आत्मकृतेः परिणामात्, Bhaskararāya seems to opine Pariṇāmavāda to be the intent of the śruti, and of Bhagavān Bādarāyaṇa.
There is clear allegiance to Pariṇāmavāda exhibited by him while explaining the below verse from the Vāmakēśvara Tantra:
तस्यां परिणतायां तु न कश्चित्पर इष्यते |
It is of course a separate issue that Rājānaka Jayaratha goes out of his way to interpret this rather direct verse as something else. So, Bhaskararāya does seem to not only adhere to Pariṇāmavāda but also suggests that all (or most) adherents of Tantra śāstra prescribe to Pariṇāmavāda (Abhinavagupta and other śaivas of Kashmir clearly being an exception to such as assumption).