Best approach to render a material composed of multiple plastic layers?

Hello,
As a test, I’d like to reproduce a pair of sunglasses which as you can see are composed of multiple layers of plastic materials.

How can I achieve that result? Should I slice the mesh to apply a different material to each slice? Or there’s a smarter solution? I think that slicing will create separation between the layers, while in the real product I don’t think you can see any separation.

Cheers

image

I was able to achieve layering of different materials without

slicing the mesh. Is this the correct way?