Poly(lactic-acid) (PLA) as a biodegradable polymer has high potential in a wide range of applications. Owing to the relatively small difference between the glass transition temperature (55-60°C) and the temperature of usage (ambient conditions) the occurring physical ageing has significant impact on the macroscopical properties of the material. Several studies have been made, by using macroscopic measurements, to find out the mechanism of ageing in PLA, but the results are often ambiguous, and there are still several open questions. To answer these, direct measurements are needed, which are able to follow in-situ the changes in the system in the nanometric lengthscale. To answer these we propose a Neutron Spin-Echo study which allows to follow the changes in the dynamics of the system in the atomic lengthscale.