What about defining your temperature using a piecewise linear function:
Temp=pwl(time, 0ns, 0, 499ns, 0, 500ns, 200, 1000ns, 200)
Obviously though this would only work for Transient simulation where time is the independent variable.
Then the only requirement is that the relevant components in the circuit do in fact change their simulated performance with temperature. Not may built-in components do this as not many have temperature coefficients, the rate of change in performance with temperature, definable. For example, the build-in resistor, "R", has a temperature parameter but just changing that does not change the resistance as Temp on its own is only used for calculating the noise contribution (kTB) of the resistance for noise analysis. To scale the resistance to temperature you need to defile values for Tnom, TC1 and TC2. Only the basic R, L and C components, and not many others, have this option.