Error in storing for loop iterations

I am trying to store the values of each for loop iteration so I could plot them in respect to time. However, it keeps giving me the error:

Array indices must be positive integers or logical values.

Error in Rheology (line 16)

s_qtz(i) = A_qtz*(str.^n_qtz)*exp(-Ea_qtz/(R*i));

I am not quite sure of what to do to fix this error. I provided my code below.

%stress array
str = [0.1, 1, 10, 100];

%Constants
R = 8.314;
A_qtz = 1.26e-5;
n_qtz = 3;
Ea_qtz = 2.42e5;

%temp array
T = [973.15:100:1373.15];

for i = T
s_qtz(i) = A_qtz*(str.^n_qtz)*exp(-Ea_qtz/(R*i));
end

Answer 1

[Image Analyst]

It's thoroughly explained by the FAQ:

https://matlab.fandom.com/wiki/FAQ#.22Subscript_indices_must_either_be_real_positive_integers_or_logicals..22

Answer 2

[Walter Roberson]

Please read https://www.mathworks.com/matlabcentral/answers/395816-why-do-i-get-array-indices-must-be-positive-integers-or-logical-values-error-when-using-angle-fu#comment_882605