Time node in material node editor?

Hello artists!
i didnt find the Time node when i am editing materials using node editor? is there a reason or a hidden place? Or is there an other way to animate values in material node editor? like when i have 2 cool materials and i want to fade from one to the other?
thank s:spin:

you have to do that using the IPO curves to vary the alpha channel.

The time node is in the compositor.