*

One of the intriguing features that indicate unconventional superconductivity (SC) in the filled skutterudite compound PrOs₄Sb₁₂ is the broken time reversal symmetry (TRS). The preliminary analysis of our most-recent results of µSR experiments in Pr_1-xNd_xOs₄Sb₁₂ of x=0.05, 0.1, 0.15 and 0.2, at 0 magnetic field, a combined exponential and Gaussian relaxation behavior was found. As T decreases, the exponential rate λ increases, while the Gaussian rate Δ has a slight decrease below T_c. The increase of Δ below T_c, previously observed in PrOs₄Sb₁₂, is not seen for x≥0.05, indicating that TRS is no longer broken. λ here is expected to be mainly dynamic in nature and has a strong temperature dependence below T_c. λ grows with increasing x, which may be due to a quantum critical point or transition below 0.05K. The origin of the anomalous shape of λ(T) in TF-μSR below T_c for of x=0.15 and 0.2 is currently unknown.