Step 1: Use the trigonometric identity.
Given,
\[
x=A\sin^2\left(\omega t-\frac{\pi}{4}\right)
\]
Using the identity,
\[
\sin^2\theta=\frac{1-\cos2\theta}{2}
\]
Therefore,
\[
x=A\left[\frac{1-\cos\left(2\omega t-\frac{\pi}{2}\right)}{2}\right]
\]
\[
x=\frac{A}{2}\left[1-\cos\left(2\omega t-\frac{\pi}{2}\right)\right]
\]
Step 2: Determine the angular frequency.
The displacement contains the term
\[
\cos(2\omega t-\frac{\pi}{2})
\]
Hence, the angular frequency of oscillation is
\[
2\omega
\]
Step 3: Find the time period.
The time period is given by
\[
T=\frac{2\pi}{\text{angular frequency}}
\]
Thus,
\[
T=\frac{2\pi}{2\omega}
\]
\[
T=\frac{\pi}{\omega}
\]
Step 4: Final conclusion.
Hence, the time period of oscillation is
\[
\boxed{\frac{\pi}{\omega}}
\]