The Woocommerce files relating to the presentation of contents (templates) are in the folder
/wp-content/plugins/Woocommerce/templates/
In this folder you can see the base templates (among others):
Archive-product.php - presents a list of products
single-product.php - product details
This single-product file fetches the data from the folder /single-product... is in that folder that you can make changes to the product page... yet in this folder you can see the sub-folder /add-to-Cart where have the models for the button.
As for changing the behavior of the button I don’t know how it will be, but it is possible!
Another important thing, do not modify files here, copy them to your theme folder so that it looks like this: .../o_seu_tema/Woocommerce/templates/... and then modify those files in your theme! If you modify them in the plugin folder you will run out of those modifications when you update Woocommerce!
http://chrislema.com/improving-the-woocommerce-add-to-cart-button/
– Adir Kuhn