linear viscoelasticity

Hello,

I have implemented a viscoelastic model (Simo/Hughes approach: Prony series for small strain)

in Abaqus using Umat and it works fine for dynamic isothermal simulations (I validated with the Prony series implemented in Abaqus).

Now, I want to consider thermal loads (I have temperature dependent stiffnesses from a DMA experiment).

How should I use these temperature dependent stiffnesses in the model?

Can anyone explain what is main difference between Linear Viscoelasticity vs qlv (Quasi linear Viscoelasticity) proposed by Fung.  As far as I understand stress relaxation function and elastic response functions separated and given in convolution form which provides "strain rate independent" results in qlv application.  

Is linear viscoelastic description is strain dependent?