The dipole moment of polymers is not a constant, it's different for every conformer. You could do a comparative study by calculations, regarding their accuracy see:

Article How Accurate Is Density Functional Theory at Predicting Dipo...

Thank you Jürgen for your answer. Are there any available data on the approximate values or a range of values for different conformers?

I'm not aware of such calculations for your particular system. I've only seen it in lectures and talks being used as a prerequisite for FTTCF calculations of biopolymers like proteins and DNA. An introduction to that method with smaller molecules can be found here, but I don't know if that is helpful for you:

Article Vibrational Raman Spectra from the Self-Consistent Charge De...

Article QM and QM/MM simulations of proteins

Thank you Jürgen! I will check them out.