Change Windows Tkinter after some time

Sun Apr 10 09:36:41 EDT 2016

I need to make a change between windows, after some time. But i am have a little bit of trouble making my code work: My windows change only when i click on button, i tried to put lambda in my command and also don't work.
import tkinter as tk # python3
#import Tkinter as tk # python
import datetime
TITLE_FONT = ("Helvetica", 18, "bold")
time_start = datetime.datetime.now()
delta_time = datetime.timedelta(seconds = 5)
class SampleApp(tk.Tk):
 def __init__(self, *args, **kwargs):
 tk.Tk.__init__(self, *args, **kwargs)
 # the container is where we'll stack a bunch of frames
 # on top of each other, then the one we want visible
 # will be raised above the others
 container = tk.Frame(self)
 container.pack(side="top", fill="both", expand=True)
 container.grid_rowconfigure(0, weight=1)
 container.grid_columnconfigure(0, weight=1)
 self.frames = {}
 for F in (StartPage, TimePage):
 page_name = F.__name__
 frame = F(container, self)
 self.frames[page_name] = frame
 # put all of the pages in the same location;
 # the one on the top of the stacking order
 # will be the one that is visible.
 frame.grid(row=0, column=0, sticky="nsew")
 self.show_frame("StartPage")
 def show_frame(self, page_name):
 '''Show a frame for the given page name'''
 frame = self.frames[page_name]
 frame.tkraise()
class StartPage(tk.Frame):
 def __init__(self, parent, controller):
 tk.Frame.__init__(self, parent)
 self.controller = controller
 label = tk.Label(self, text="This is the start page", font=TITLE_FONT)
 label.pack(side="top", fill="x", pady=10)
 button1 = tk.Button(self, text="Go to Time Page",
 command=lambda: controller.show_frame(self.start_Counting()) )
 button1.pack()
 def start_Counting(self):
 global time_start
 time_start = datetime.datetime.now()
 return 'TimePage'
class TimePage(tk.Frame):
 def __init__(self, parent, controller):
 global delta_time
 tk.Frame.__init__(self, parent)
 self.controller = controller
 label = tk.Label(self, text="This is Time Page", font=TITLE_FONT)
 label.pack(side="top", fill="x", pady=10)
 self.time_exit = tk.StringVar()
 self.time_exit.set('%s' %datetime.datetime.now())
 label2 = tk.Label(self, text=self.time_exit, font=TITLE_FONT)
 label2.pack(side="top", fill="x", pady=10)
 button = tk.Button(self, text="Go to the start page",
 command=lambda: controller.show_frame("StartPage"))
 button.pack()
 def update_Page(self):
 global time_start, delta_time
 #print('Executou o atualizar')
 time_until = delta_time - (datetime.datetime.now() - time_start)
 self.time_exit.set('%s' %time_until)
 if time_until <= 0:
 self.controller.show_frame('StartPage') # Go to the start_page after 5 seconds
 self.after(1000, update_Page)
if __name__ == "__main__":
 app = SampleApp()
 app.mainloop()